please explain co2 for a planted noob

I (my wife) have a 72 bowfront with a few pleco's and misc mixed barbs and tetra's. it was inherited from someone that lost interest, gee i wonder why, pleco's are dull boring fish. anyways.. due to its plainness, and the fact that i have a 20lb co2( ) tank for my calcium reactor, i thought a nice planted tank would be cool. However, i dont know squat about co2 injection for plants. The equipment i have is top notch for the FW world so what do i need to do to add the co2?

72 bowfront
eheim professional 2 canister
36w UV sterilizer that i never use
K1
aquaclear powerhead
aragonite sand with gravel
lots of driftwood
NO 48" AGA light (planning 2 bulb T5)

 

basic bubble counter(dont have to have one but it helps)
glass bubble diffuser(go ebay unless you have the dough for a ada one)
drop checker (little glass thingie that has liquid in it that turns colors in relation to desolved co2 in water, to much co2= dead fish)

i think thats everything since you already have a co2 tank and needle valve