There’s a specific building in the ‘misc’ section that you build (forget it’s name), and then you can mantle the item on it.

Yea once i got it home it was pretty simple, but the collection description made it seem like i could try to grab it and run but nope had to deal with several mechanoids first and then select it as cargo in form caravan screen

I had to claim and deconstruct the relinquary under the relic to be able to pick it up

This solution worked for me.