Making a Pull Request
In GitHub Desktop go to your fork and click Pull Request in the upper right corner. Then, enter a title and a description.
You might want to check you are creating a request to the right fork.
In this picture the right side with the arrow coming from it should just say master.
The left side with the arrow pointing to it should say PhyXTGears-2017-Bling/master.
Click create pull request and click on the link to view the request on GitHub.
Once you have clicked on the link and opened the GitHub website, you can add comments. Check back often to see if your pull request was accepted.