How do I get there? I can’t find the way.
Do the story.
Complete the metas and hope it’s one of the rooms you get sent to.
Teleport to friend stone
It looks like they fixed it today, according to the patch notes.
"Fixed a bug in which the Hammer's Hoard point of interest could not be activated from outside of the gate."
There are two points of interest locked behind these gates: One at the purple gate (can be entered with Story Quest or with purple plate) and one at the green gate (can be reached by running to the door, since today). So, you still can not do map completion without Story, Meta Events or Mesmer).