I used to hunt with a 150 lb Astro Daco Hornet, so I assume that yours must be similar to mine.
To string the bow, I found it best to take the bow off the stock, stand on the one side of the bow, and pull the other side upward with the loop in your string ready to slip over the end. Make sure the loop will fit over the end of the limb before pulling your guts out. The strung bow can then be re-mounted to the stock.
To cock the bow (if you're right handed), put your right foot in the stirrup, resting the stock against your left hip. Lean forward, and grasp the string with both hands (one on either side of the stock) keeping the knuckle of each index finger against the side of the stock. By straightening up using a combination of your back and leg muscles you should be able to cock the bow.
By keeping the knuckles of your index fingers against the stock, you keep the string centred for accuracy.
My bow had a lever/button at the tang, just behind the mechanism, that had to be pushed forward at the instant the trigger was pulled to discharge the bow.
Be sure never to dry-fire the bow.