Once `yarn start` has built the assets it will continue to do so whenever any of the files change. This means you don't have to manually build the assets whenever you've made a change to the code.
Next, we'll build the web server that will serve the frontend assets we just built.
### Backend
Build and run the backend, by running `make run` in the root directory of the repository. This command will compile the Go source code, and start a web server.
By now, you should be able to build and test a change you've made to the Grafana source code. In most cases, you need to add at least one data source to verify the change.
Run the `setup.sh` script to setup a set of data sources and dashboards in your local Grafana. The script creates a set of data sources called **gdev-\<type\>**, and a set of dashboards located in a folder called **gdev dashboards**.
Some of the data sources require databases to run in the background.
Installing and configuring databases can be a tricky business. Grafana uses [Docker](https://docker.com) to make the task of setting up databases a little easier. Make sure you [install Docker](https://docs.docker.com/docker-for-mac/install/) before proceeding to the next step.
In the root directory of your Grafana repository, run the following command:
```
make devenv sources=influxdb,loki
```
The script generates a Docker Compose file with the databases you specify as `sources`, and runs them in the background.
See the repository for all the [available data sources](https://github.com/grafana/grafana/tree/master/devenv/docker/blocks). Note that some data sources have specific Docker images for macOS, e.g. `prometheus_mac`.
- Learn how to [Create a pull request](/contribute/pull-request.md).
- Read [How to contribute to Grafana as a junior dev](https://medium.com/@ivanahuckova/how-to-contribute-to-grafana-as-junior-dev-c01fe3064502) by [Ivana Huckova](https://medium.com/@ivanahuckova).