Update core doc (#13324)

* Updated core documentation

* Update README.md

* Update api_details.md

* Update api_details.md

* Update src/core/docs/api_details.md

Co-authored-by: Tatiana Savina <tatiana.savina@intel.com>

* Update src/core/docs/api_details.md

Co-authored-by: Tatiana Savina <tatiana.savina@intel.com>

* Update src/core/docs/api_details.md

Co-authored-by: Tatiana Savina <tatiana.savina@intel.com>

* Update src/core/docs/api_details.md

Co-authored-by: Tatiana Savina <tatiana.savina@intel.com>

* Fixed comments

* Update src/core/docs/debug_capabilities.md

Co-authored-by: Tatiana Savina <tatiana.savina@intel.com>

Co-authored-by: Tatiana Savina <tatiana.savina@intel.com>

src/core/README.md

@@ -18,20 +18,17 @@ OpenVINO Core has the next structure:
  * [builders](./builder) is obsolete component which provides helper methods for operation creations. Please don't use this API, and use public OpenVINO API instead.
  * [dev_api](./dev_api) contains developer API. In order to use this API, you need to link your component against `openvino::runtime::dev`.
  * [docs](./docs) contains developer documentation pages for the component.
- * [include](./include) contains public API. Detailed information about provided API can be found [here](#TODO).
+ * [include](./include) contains public API. Detailed information about provided API can be found [here](./docs/api_details.md).
  * [reference](./reference) is a library which provides reference implementations for all supported operations. Operations with evaluate method use these implementations inside.
  * [shape_inference](./shape_inference) library contains implementation of shape inference for OpenVINO operations.
  * [src](./src) folder contains sources of the core component.
  * [tests](./tests) contains tests for OpenVINO Core components. More information about OpenVINO Core tests can be found [here](./docs/tests.md).
 
-## Debug capabilities
-
-OpenVINO Core contains a set of different debug capabilities which allow to make developer live a little bit easier.
-Different debug capabilities supports to collect information about object statuses in the process of OpenVINO Runtime execution.
- * OpenVINO Model debug capabilities are described in the [OpenVINO Model User Guide](https://docs.openvino.ai/latest/openvino_docs_OV_UG_Model_Representation.html#model-debug-capabilities).
-
 ## Tutorials
-  TODO
+
+ * [How to add new operations](./docs/operation_enabling_flow.md).
+ * [How to add OpenVINO Extension](https://docs.openvino.ai/latest/openvino_docs_Extensibility_UG_Intro.html). This document is based on the [template_extension](./template_extension/new/).
+ * [How to debug the component](./docs/debug_capabilities.md).
 
 ## See also
  * [OpenVINO™ README](../../README.md)

src/core/docs/api_details.md

@@ -0,0 +1,30 @@
+# OpenVINO Core API
+
+OpenVINO Core API contains two folders:
+ * [ngraph](../include/ngraph/) - is a legacy API, this API is no longer being developed. Only aliases to new operations and operation sets extend this API.
+ * [openvino](../include/openvino/) - current public API, this part is described below.
+
+## Structure of Core API
+<pre>
+ <code>
+ <a href="../include/openvino">openvino/</a>                  // Common folder with OpenVINO 2.0 API
+    <a href="../include/openvino/core/">core/</a>                   // Contains common classes which are responsible for model representation
+    <a href="../include/openvino/op/">op/</a>                     // Contains all supported OpenVINO operations
+    <a href="../include/openvino/opsets/">opsets/</a>                 // Contains definitions of each official OpenVINO opset
+    <a href="../include/openvino/pass/">pass/</a>                   // Defines classes for developing transformation and several common transformations
+    <a href="../include/openvino/runtime/">runtime/</a>                // Contains OpenVINO tensor definition
+ </code>
+</pre>
+
+## Main structures for model representation
+
+* `ov::Model` is located in [openvino/core/model.hpp](../include/openvino/core/model.hpp) and provides API for model representation. For more details, read [OpenVINO Model Representation Guide](https://docs.openvino.ai/latest/openvino_docs_OV_UG_Model_Representation.html).
+* `ov::Node` is a base class for all OpenVINO operations, the class is located in the [openvino/core/node.hpp](../include/openvino/core/node.hpp).
+* `ov::Shape` and `ov::PartialShape` classes represent shapes in OpenVINO, these classes are located in the [openvino/core/shape.hpp](../include/openvino/core/shape.hpp) and [openvino/core/partial_shape.hpp](../include/openvino/core/partial_shape.hpp) respectively. For more information, read [OpenVINO Shapes representation](./shape_propagation.md#openvino-shapes-representation).
+* `ov::element::Type` class represents element type for OpenVINO Tensors and Operations. The class is located in the [openvino/core/type/element_type.hpp](../include/openvino/core/type/element_type.hpp).
+* `ov::Tensor` is used for memory representation inside OpenVINO. The class is located in the [openvino/runtime/tensor.hpp](../include/openvino/runtime/tensor.hpp).
+
+## See also
+ * [OpenVINO™ Core README](../README.md)
+ * [OpenVINO™ README](../../../README.md)
+ * [Developer documentation](../../../docs/dev/index.md)

src/core/docs/debug_capabilities.md

@@ -0,0 +1,10 @@
+# OpenVINO Core debug capabilities
+
+OpenVINO Core contains a set of different debug capabilities that make developer life easier by collecting information about object statuses during OpenVINO Runtime execution and reporting this information to the developer.
+
+* OpenVINO Model debug capabilities are described in the [OpenVINO Model User Guide](https://docs.openvino.ai/latest/openvino_docs_OV_UG_Model_Representation.html#model-debug-capabilities).
+
+## See also
+ * [OpenVINO™ Core README](../README.md)
+ * [OpenVINO™ README](../../../README.md)
+ * [Developer documentation](../../../docs/dev/index.md)