Need assistance with git workflow

I am going to review pull request.

For this purpose I am going to pull down according branch.

This is repository
My status there - collaborator

This is pull request

The thing is - this PR is from fork.

My experience with reviewing for now - it’s all about PR-s form owner or from other collaborators. So I used pretty simple workflow to pull down their branches:
git pull
git checkout <branch name>

For this one, from fork, this doesn’t work - I can’t see the needed branch in the list of remotes, so I have no access to it.

I did some research, I guess I need to change local git config, but there are several suggested options, discussion on stackoverflow is not very clear for me.

So any advice would be appreciated. Let me know if any additional info is needed.

Solved

used ID of pull request in fetch command:

$ git fetch origin pull/ID/head:BRANCHNAME

If somebody knows if there is some side effects to this method, or knows any better way to do this, please let me know.