Do you know the metro number for the PowerZone and also the tram number to get to the Melkweg? Ira
For detailed instruction on the tram to the PowerZone watch this video:

Melkweg tram:
Leidseplein can be reached via trams 1, 2 and 5 (about 10 minutes from Amsterdam Central Station) and lines 6, 7 and 10 (about 7 minutes from the metro station Weesperplein). The bus routes 170, 171, 172 and the late-night busses 72, 73, 74 and 78

Source: hightimes.com