Clone the repo:

git clone git@github.com:meetmangukiya/quast.git`

Create a new branch:

git checkout -b <username>/<issue_number>

Edit files.

Add files to commit:

git add file1/path file2/path

Commit:

git commit

Enter commit message and save.

Push the changes:

git push origin <branch_name>

Branch name was that was used in step 2.

Create a pull request:

1. Go to https://github.com/meetmangukiya/quast
2. You should see your branch highlighted above the repo code. Click that button.
3. Done!