How do I make a custom user interface of tables?

All of this can be handled in UMG quite easily. Use horizontal and vertical boxes to create table like elements. Otherwise, it looks pretty straight forward to do in UMG. The tabs on the left can be either buttons that turn on/off visibility to elements within the same UMG widget, or can be a separate widget that can bring up other widgets. There are some good tutorials to get you started here: UMG UI Designer | Unreal Engine Documentation
Does this help?