[EclipseGST]

Its very simple if you have open spaces... If its breakers, 9 times out of 10 you have 240v at the main. Get a roll of wire, 3 or 4 strand, usually go with 10/3 or 8/3 depending on amps you plan to run through it. You buy a 2 pole breaker (whatever amperage you need), pull the cover off, place breaker on the board, hook black wire (hot) to one pole and red wire (hot) to the other pole on the same breaker. White (neutral)/Green (ground)/Copper (ground) all go to the ground block.

If you have Black, White, Green wires... Use Black and White as your 2 hots and Green/Copper as ground/neutral.

I'm sure you can find a diagram on google images. Very simple.