For the “Go Do Heroes Things” quest in Immortals Fenyx Rising, you will need to visit Guardian Island, and remember the labors of Herakles. This plays out as a minor puzzle, with multiples areas with pressure pads, and different solutions to all of them.
Each areas is marked by a numeral. You might think you need to do them all, but only one of them will be correct. The rest will be just hard work for no reward, just like Herakles himself as people kept piling more labors on him.
The correct answer is twelve, and you can find the correct puzzle to solve to the left at the very start of the area. You will see a red circular tile with XII on it. This is the area you will need to solve. Thankfully, doing so isn’t very hard. There are two pressure pads, one anvil that will need a heavy weight, and a feather that will need a light weight.
You can find one weight trapped in the red matter of Typhon, so just smash it with melee attacks, then drop it on the feather pressure plate. If you walk up the stairs into the back room, you can find two more weights, and you can put them on the anvil pressure pad.
When both pads are pressed down by the weights, the giant stone Cerberus will open his mouth, and you can go inside to complete the mission. Be sure you grab the Ambrosia in the left head before you do. Inside the mouth, you will find the entrance to a Tartaros Vault.