The Resources merit requires special handling in pledges, due to the way the book defines its benefits. Every character has a primary resources merit (even if it has zero dots). There are two options for gaining more resources from a pledge:
The pledge can add dots to your primary Resources merit. As usual, you can't increase this merit past 5 total dots.
The pledge can grant you a new secondary Resources merit. Secondary Resources merits are static and cannot be enhanced by any other pledges. The upside is that you can have as many Secondary Resources merits as you like.