This should get you started...
1) Project >> Configure from the menu.
2) Click buttons
3) Click on a blank button, one in the left-mouse button section would probably be best.
4) Type in the button name, colors, etc.
5) Click new entry button (one button can trigger one or many actions)
6) Select an "AmigaDos" action. (click the "swirl" icon)
7) In the command text section: unzip {f} -d {d}
On your "flags" might want to check Rescan Destinatin and rescan source.
9) Hit Okay, Okay, and Save
This button will unzip one selected zip to the destination selected in the other window. You can probably make this work for multiple ZIPs by modifying your command string. Check out the {} button in the new button window for available tokens. This also assumes unzip is in your path.
This is how I did it, but I'm still learning Opus.. Others may have cleaner ways...
