Unsure about image size for large-scale banner printing

I'm pretty new to all this and I'm especially unfamiliar with printing

I've been asked to design a banner that will be 16 ft x 8 ft - what should my canvas dimensions be? If I'm using Illustrator as long as the ratio is 2:1 does it matter how large the canvas is?

This site says to use 100 dpi to avoid files that are too large. I should heed this advice, right?

Thanks so much!

Great design resource

100 Things Every Designer Needs to Know About People (Voices That Matter) Submitted January 02, 2018 at 11:14PM by steph-was-here http://ift.tt/2CGUrzj