Acrylic sign leds for bases - cut, solder, what?

Hi
I am going to try to make some acrylic signs and I am looking for sources for leds for bases -Then once you get them, do you cut them to length? and after you cut them, do you solder them or what?
I got out of electronics when the vacuum tubes went out?
Thanks,
Martin

There are specific points where you can cut the strips. It is also imperative to keep the polarity correct