Why do you want to build? That is the first and most important question. If you want to go sailing, seriously consider buying instead! If you have not built a boat before, you will not save much by building the hulls yourself. Most of the cost of a boat is in gear, fittings, rig, sails etc. not the hulls.

If you want to build a boat for the experience, then you have an adventure ahead of you. If you "just" want to save some money, you need contacts and skills you will not have until the end of the project at the earliest. We have done this before, sourced rigs (old Tornado rigs) and gear for free or very low prices, building our own sails and trampolines etc.