How to combine multiple Goole GPS Tracks (.KMZ) so you can see all them together on one map and save this as new track?

How to combine multiple Goole GPS Tracks (.KMZ) / MyTracks so you can see all them together and save this as new track?

Goto https://www.google.com/mymaps, select 'new map' and add as much layers on the left side as you want. For every layer you import a corresponding Google GPS Track File (.KMZ)