Basically it's remove the crankcase drain plug, remove the oil filter, after the oil drains out replace the drain plug snuggly, dip your finger in clean engine oil and smear it round the rubber gasket on the new filter and install it hand tight + 1/2 a turn and refill with the appropriate amount of fresh oil.
Be sure to have the bike over a pan deep enough to hold up to 4 or 5 qts. when you remove the drain plug.....It's a pretty straight forward job, be sure you take out the engine oil drain plug, not the transmission drain plug. On a big twin the engine oil drain is sideways while the trans drain is straight down, I'm not sure if they follow that pattern with the Blast. It's an easy job but if you're unsure then you need a manual of some sort, either chiltons or a factory manual or you can take it to a dealer or an independent HD shop and see if they'll let you watch so you can learn...
I take it you're a fairly new rider, it's commendable that you want to learn basic maintainance but you really need a manual of some sort to give you a basic understanding of what you're doing. You can pick up a basic tool set of sockets and box end wrenchs at Sears for a reasonable price, look for a 3/8 drive ratchet and socket set and a box end wrench set from 3/8 up to 15/16 or so. At some point you'll also need a set of torx sockets as well as allen wrench sockets and the usual phillips and straight screwdriver, some channel locks and a rubber mallet should cover your needs for anything you're liable to do at home.
Good luck, double check your work and ride safely.
You should add - Wipe the oil-filter mating surface with a clean shoprag. Two reasons: cleans the surface so no dirt and debris gets-into the oil, and ensures that it's impossible to "double gasket" the filter (i.e. when the gasket from the previous filter is accidentally left on the mating surface - very bad to do this)