How do you manage assets and projects by working in team? Version Control?

I can’t find a good information source about artists’ teamwork. How can 2-3 artists (distributed team) work together on one level using Version Control (git etc.)?
I do not see good git diff-tools for assets. How version control can be used without diff-tools? How do you make merges?
How do you overview changes made by other artists?
How do you make backups (if you are not using version control)?
How does look your pipeline?

Sorry for these silly questions, but it is very important for me to understand the workflow.

Thank you in advance!