How can I prototype my ideas?

You want to build something that is enough to put in front of someone to evoke a response and get some feedback. Think of it like the 'shop window'. You don't need to invest lots of time and resource to make it perfect because you'll have to tweak it again after you get feedback. Early stage prototypes are essentially mock-ups and can take different forms: landing pages, Facebook ads, brochures, leaflets, part of a monthly pack etc.