Nosing up into a stall could be overcontrolling on your part, or it could be that the plane is not properly balanced or trimmed.

Overcontrolling is very common when you're learning. Trust me, I know! You can reduce the control throws by moving the pushrods to the outermost holes on the control horns, or the innermost holes on the servos arms, or both. You may also be able to reduce the throws by programming your transmitter.

For balance issues, you'll have to find someone who is experienced with the Slow Stick. Hopefully, such a person will join this thread. Or you can search for Slow Stick info on this forum or on RCGroups.com or WattFlyer.com. The Slow Stick is extremely popular, so there are many discussions about how to set it up.

Typically, you can expect the plane to climb gently under full throttle with the elevator at the neutral position.

EDIT: Here's a major thread about the Slow Stick. I'm sure you can get some help if you post in this thread:
http://www.wattflyer.com/forums/showthread.php?t=7237

- Jeff