POST request to GitHub API that creates a pull request.

I’m trying to contribute to my first open source project. It is an app that contains a list of projects to contribute to on GitHub. The feature I’m trying to implement is to add a form to the app to take a suggestion for a project to be added to the list on the app. When the user submits the form, a pull request to the repo must be created. Does anyone have an idea how I can begin to approach this?