Hi oboeash, Welcome to the forum...
You could start setting up your system. It'll take a while for the water to cycle anyway.
You mentioned your garage...is that where your planning on having your system ? What kind of fish were you thinking about ?

I started a small system with a 55 gal tank, inside when I first got started. I did have a couple plants to play with.
see bottom of page 2 and page 3...
Dave's ground breaking news.

I'm not using plants now, just the solids seperator and the bio-filter. Well, actually I have duckweed floating in the solids seperator , which I feed to the tilapia.