From my understanding of the kits, they only come with the electronics, motors, chains, and all hardware needed to assemble the sled and attach the motors to your frame of choice (maybe a sled depending on the version of the “kit” you buy). What is usually needed is the router, and then wood and hardware to build said frame of choice.
Take a look at the following link: The Maslow Manual V 0.001 as this should help you understand the process of how to get up and running, as well as helpful detail in building your frame. This is a really great community on here, and there is a wealth of knowledge if you get stuck somewhere.