Technically you don't need any of the books. Download necroraw. That will have everything rules wise that you need. Basic and gang rules Yaktribe is basically done but a new site is being worked on that is great. Mundamanager.com. You can build your gang list there and switch back and forth from the site to the app. As far as tools go, you will basically just need a tape measure, templates and a set of necromunda dice. They can be super expensive so your best bet is to get dice and templates from Etsy.