Recording a movie from Matinee: Guide to using codecs to lower output file size?

I am doing test renders of a short matinee sequence (about 15 seconds) and the output file size without a codec (as a .avi file) is approaching nearly 4 gigs for a 15 second clip. That’s a but unacceptable since the complete sequence will be about 5 and 1/2 minutes long.

I have tried searching for guides on how to input something into the “codec” box, but nothing I have entered has worked/changed anything, and the guides are all pretty vague. Does anyone have any information on this they can share so my output files are not 1 gig per 5 seconds?