Suggestions on learning to use Rollers
I had the same problem as you when I bought my rollers, the best advice is to place the rollers in a door frame. Start by holding onto the doorframe and get used to spinning with one hand on the bike.  

You should always try to maintain a high cadence (and speed) when you first start, the momentum will help you balance. The plan is to pedal in a perfect circular motion, no pedal mashing! Focus is very important too, keep your body calm and try to focus into the distance to aid your balance.

Aside from that, it'll take a few weeks to get used to it. But once you have, the benefits of rollers are incredible, you'll notice it on rides out. 

Good luck!