This 4' by 8' layout uses standard switches to make spur sidings and a passing siding. It is a variant of one of the most popular layout types in all scales.
Here we append the previous layout (#8) to the left corner of the oval layout. You can treat the oval layout as higher ground, and thus would connect with the switch at the bottom of the portside layout. If it is water-level, then connect as shown with the pierside line of the portside pike.
Connecting at the opposite side from the lower freight siding of the portside layout. The long passing siding of the oval layout can be elevated slightly, passing over the pier with a three-track bridge as shown. Naturally, these are only examples. You can use the same principles to expand by connecting with other layouts.