Place a workbench on all islands of area 1, 2 and 3
You can do this either after you finish the game or as you progress. You do not have to place a new Workbench on each Island. You can use the same Workbench for all of them. Just place it down and break it to pick it back up. The only Islands that are required are those with pathways connected to the Story Islands (No boss levels, no Ghostworld, no purchasable Islands, and no Event-specific Islands).
The list of Islands required for this trophy can be found under Great Explorer. Once you have placed the Workbench down on all the Islands, the trophy will unlock.