Open the project in android studio and go to File -> Settings -> Version Control -> Git.
Click on test button to test "path to Git executables". If successful message is shown everything is ok, else navigate to git.exe from where you installed git and test again.
Go to File -> Settings -> Version Control -> GitHub. Enter your email and password used to create GitHub account and click on OK button.
Then go to VCS -> Import into Version Control -> Share Project on GitHub. Enter Repository name, Description and click Share button.
In the next window check all files inorder to add files for initial commit and click OK.
Now the project will be uploaded to the GitHub repository and when uploading is finished we will get a message in android studio showing "Successfully shared project on GitHub". Click on the link provided in that message to go to GitHub repository.