can i install WP locally on Mac without using a hosting site?

Help! Am getting stuck trying to install WordPress locally on my Mac. Got right to the final set of instructions (5 minute test) but when I try to manually create a figuration file I am asked for a username and password, which it prompts me are my MySQL username and password. I have never set these up so don’t know what they are. I don’t really know what I’m doing, but basically I haven’t registered a domain name or paid anything to a hosting site as yet – I wanted to download WordPress and try and see if I can actually figure out how it works before I do that. Is that where I’m going wrong? Do you have to have a host before you can do this? Any help gratefully received!