I have an Armorist. How do I make Bound or Summoned Equipment?
Any Armorist (well, technically any character that has either Bound Equipment or Summoned Equipment as a class ability) should get a new tab called "Bound/Summoned Equipment". On this tab, you can designate items as Bound or Summoned equipment. Items so designated will receive the following benefits: they'll be marked as masterwork items (if they weren't already), they'll be marked as "free" so that they don't count against your character's total wealth, they'll have their weight set to zero if not equipped (because we assume the item is either being used by someone else or simply not currently manifested), and will be findable by any other special abilities that interact with Bound or Summoned gear (such as the Warden archetype's Deadly Guardian ability).
I picked a Bound/Summoned item from the menu, but the selector doesn't show my weapon/armor/shield/staff.
When you first purchase an item that will be Bound or Summoned gear, make sure to select it as a Custom Item (under the top heading on the tab labeled "Magic, Custom & Masterwork Weapons/Armor". Those items can be customized, and that is what the tab looks for.