The most important part of any model railway is the base board, so “How to build model railway baseboards”
A base board of some sort is essential for any model railway, you can either build your own from scratch, using a sheet of ply, and a timber frame, or you can get a laser cut one from a number of different manufactures, if you’re looking for something more custom these can also help you with that. For micro layouts off cuts of wood, box files and even flat pack shelves have been used.