Their are two ways to capture altitude using the autopilot.
1. Manualy climb the herc to 3000 ft, hold it level and then engage the "altitude" button. It will hold the altitude  you were at when engaged.

2. Engage the "altitude" button and using the "pitch" slector you increase or decrease until you get the required altitude and level off.

The autopilot depicted on the Herc has no automated altitude capture facilities so it is all manual.

Hope this helps.

Dax