It is the most difficult for beginner to create Multiple Pull Request in GitHub they say that the Previous PR commit merge with it.
Before following the steps given below create a PR
git fetch --all
This command will fetch all the data from upstream and origin to your local repository
git reset --hard origin/master
This is the most Important step so what happen is that our local repo contain previous commit in it so we have to remove it before new committing so we write the above command which simply reset the local repo as remote repo's master branch. This will set the local repo as the last merge Pull Request...
Watch the Create Multiple PR to GitHub Tutorial Video
It will help you the best
Hope that this Post helps you