Acropora as well as most all other SPS corals are very easy to propagate. It is as simple as breaking off a branch and attaching it to another piece of rock or rubble with some super glue gel. I use Ross brand super glue gel because it is cheap and readily available but just about any cyanoacrylate based gel super glue will work. Make sure you buy "gel" type super glue. If it doesn't say "gel" on the package it will probably have a very thin consistency and not stick to the frag after you cut it.
Here is the coral I will be fragging -