Multiple people working on Same Project

Hi, I am new to UE4 and trying to figure out how multiple people can work on the same project at the same time. I created a simple scene with three levels and I’m using SVN as my source control.And 3 different people are working on same project but on different level, and the project is kept on shared network drive. While saving the file i sometime keep getting errors. I’m copy pasting the screenshots of the errors below.

Can someone show me what it is that I’m doing wrong or if there are any tutorials that show how to use source control will be greatly appreciated. Thanks!