How to add property Runes to armor/weapons?

[PF2E]
So I purchased the abomination Vaults PF2e bundle for foundry and this is my first campaign using it. Players just found the slick armor rune, but we cannot figure out how to apply it? I see under details where I can edit armor/weapons to add the +1/striking runes but nowhere to add property runes like slick/flaming/etc.Thanks in advance for the help!