Merge Request Conflict from personal Fork

I got a merge request from a personal fork to my repository which is reported to have conflicts and the UI suggests to make a manual merge. But in general the personal fork is as it says: personal and not visible for me so the suggested steps are not applicable. In addition I can’t really see what the conflicts are. I opened the web UI and in fact there are special notations which may indicate what went wrong. But I found no way to resolve and commit from there.

In this very special case I got access to the personal fork (which in my opinion should not be necessary) and resolved the conflict manually as suggested. So for now I’m fine but I’m wondering what ist the correct way to go. Any hint to the doc / FAQ?

Doing so I forget to approve the merge request before doing the manual merge. In the UI anything looks fine but I can’t post-approve now. Is that so?