A few collaboration questions

I briefed the wiki and setup a perforce server that the developers have connected to. However, how does the engine handle two people editing a file at once? Or, even such as a level? Can two people not work on a level at the same time? I am having a hard time seeing this as a restriction as many games on the unreal engine have loads of level designers and I highly doubt they are all taking turns. Any help is appreciated.

I’m no expert but I believe only one person can work on the Level itself. That doesn’t stop others to work on props in that level, which would then be updated when they commit and you update.