Not a noob question at all; a Bitcoin at 30Gh/s takes 75 days to mine maybe quicker depending on the mining pool you join. (the mining pool increases your earning potential due to many hands making light work)
You literally need to download software such as BFGminer, join a mining pool (BTCGuild) and have a bitcoin wallet to send the money to (coinjar.com) once you plug the miner in, it's running in seconds.
The best advice I have with mining is....don't look at it based on the current value of a bitcoin, it's still speculative and due to limited supply, people are convinced it will top at $10,000 a coin once more retailers get on the band wagon of accepting them for payment. Only today a big US online store started taking them.
The best thing with mining gear is to run it for a couple of months, keep the coins, sell the rig and get a faster rig. As with computers etc etc the speed of the rigs gets quicker every 3-6 months. Demand has been so high for the newest miners that pre-orders can't even deliver until March AT BEST. I was lucky with my one. But now have two miners that aren't really needed. But hey, realistically while you wait to sell, you just plug them in and earn coins. I'm tempted to do it with the 50Gh/s unit as it's actually specced closer to 60Gh/s So that's a Bitcoin in 25 days running alongside the 30Gh/s one