Lighting a collector dollhouse
So we see you're serious about dollhouses. Willing to risk minor shock and accepting the frustration of learning electricity is a testament to your commitment. We can't make it easy, but we should be able to guide you along the way.
Cheaper and a fair bit easier
Basically all you need for the twin wire, or socket strip, method is a socket board, a transformer, and your light fixtures.
Each fixture generally comes with about 60 centimeters of wire which can be strung however necessary. In this case, you'll simply string it through the wall, with as little wire showing as possible, and connect it to the socket board, wherever you have it positioned. The socket board has a couple dozen holes to accommodate plenty of fixtures, and it can easily be attached to the transformer to work in an ordinary outlet. Wiring a dollhouse is actually pretty easy, the majority of your problems will come from arranging your fixtures and positioning the wires and socket board(s).