That's great
It is very simple to add bins directly,though I don't think I've ever seen any videos on it unfortunately.It's essentially the same process as making windows for ventilation,except you'd want to make holes lower on the bins for the hamster to have easy use of each bin.There have been lots of tube-connected bins,and sadly those just aren't true expansions.
It is good to watch videos and figure out at least the cutting part and maybe determine if there are alternative tools you could get locally,other than in a pinch using a wood burning knife as long as it has a good blade attachment.Then you can just apply the window technique but modify it,then connect two or more bins together with zip ties!It may sound complicated,but that's just because explaining it becomes complicated while the process itself is fairly simple.