Just one last question when i press the approach button...what other buttons should be on, like alt, y/d, hgd/nav etc?
Heading and Alt.
Once the Autopilot acquires each of them, it turns them off itself. Just make sure you have your NAV/GPS selector set to NAV, and that you press the APR button while the glideslope indicator is above you - it acquires the glideslope from above, not below.