first time with a Brisket....HELP

Smoke it until it's done...  It should feel like butter when you probe it.  Cook time is dependent on variables you didn't provide, what temp are you cooking it?  Most go 225 - 275 degrees, in that range you're looking at 1.5 - 1.25 hrs/pound usually.  There's a lot of Brisket cooking tips and techniques here to check out.  I'd say set it up for 250 degrees, put a temp probe in it to monitor temp and let her roll until you get to 195 -200 IT and start probing it for that buttery feel.  When you have that she's done and ready to rest for slicing.  Obviously rub it with your rub of choice, many options there.  5 pounder is probably a minimum of an 8 hour cook so give yourself extra if you have a deadline to hit.

Dude, you can't put too much lump in there. As long as you can get your indirect piece in. You can always use it later.