How to review submission?

I am a newbie here. I just completed a project, and I have a number of submission to review. How can I review them? Can I see one by one?

Since I used an external platform, some participants made a mistake at the end and click on the final button of the external platform instead of clicking on the URL-Prolific link for completion.

I think I have many submissions that are good but did not return any completion code.

how should I proceed?
[I already asked to help center and I am waiting for a response]