You can import scripts. That's an option you can find in Manage Scripts...
You can copy and paste all the layout objects from a layout in one file to a layout in another, but you have to be very meticulous about this and get other parts of your database set up correctly first. (The layout needs the right name, it as to refer to the correct table occurrence, you may have value lists that need to be defined first...)
You often have to paste the same layout objects twice in order to have buttons that work.
(Paste layouts, Import scripts, delete layout objects, paste them again.)
Your imported table may have calculation fields that are enclosed in /* comment brackets */ and you have to fix the error that caused this (Such as a missing table occurrence) and then remove the brackets.
It's usually much simpler just to keep your tables separate and link them via a table occurrence in Manage | Database | relationships. You can use this approach to link tables in separate files just as though they were present in the same file.