Dart if you want to you could buy a blank already made up and ready to go. If not you will need to decide what type of wood you will use and cut it into strips 1/4"-3/8" thick, then epoxy it back together making sure to cross thread the grain of the wood to make your blank more solid, then off you go!! This is just a quick summary of how it goes but if you need to get into more depth feel free to ask. There are many gun builders on this site and it is alwayz better to get more than one opinion and then decide for yourself what is best!
Aloha bruddah Keoni