When you do something like

git flow feature start FEATURENAME

It will create a branch called feature/FEATURENAME and it will be copied from the develop branch.

From here, you can make your code changes as needed and then make your git commits as you normally would.

If you are wanting to move your work over to another computer, you can call git flow feature publish and it will create the branch on the remote repository. You can then checkout the feature on the other computer.

When all changes and commits are made, you call 

git flow feature finish #optionally passing -m 'COMMIT MESSAGE'

and this will merge your commit back into the develop branch. Alternatively, you can publish your commit again to the remote repository and then create a merge request.