Did you get just the engine or did you get the whole kit like
THIS. That kind of engine is not something youd typically put in an RC and especially not a crawler. Crawlers dont do so well with nitro/gas engines. They are generally electric.
As for the engine/kit did it not come with instructions on how to put it together? As for what else you need its kinda hard to say without knowing what you currently have or what your ultimate goal to build is. If its a crawler you're after then you're going to want to go electric which means aside from the kit (The SCX10 III is popular) You'll need an electric motor and electronic speed controller (ESC), high torque servo, LiPo battery, LiPo battery charger, and a transmitter and receiver. Once we zero in on what you really want then we can talk specific brands/models of components to buy.