To begin with you will need to locate and study suitable boat plans. The internet is an excellent resource for this. There are both free and paid plans available online. The free options may not be so extensive or detailed though you may be lucky and find a design that comes at no cost and contains all the information you are after.
There is also software that you can use to create a unique individualized plan. Though in most cases such tools are not free of charge they can be a good investment as you will be able to create a vessel that is perfectly suited to your needs and wishes. This is often better than choosing a plan that has cost you nothing but will not result in the type of boat that you are after.
Of course you will also need adequate space for the project. Keep in mind the timeframe that you think it will take to complete the boat. You may want to devote a few months or as much as a couple of years in to building your very own boat.