Basic texture structure should have a fill layer at bottom, any additional layers on top, all placed in a group that has a black mask applied to the group and reveals the targeted mesh areas.
A UDIM, or texture set, is a set of UV islands laid out in one of the UDIM areas (e.g., UV 1001, UV 1002, UV 1003, UV 2001, etc . . .). UDIMs are typically used for look development and/or film and vfx. UDIMs are useful when you want to group areas of the mesh that will have the same material together, and apply a tiling material across that UDIM. It is similar to Texture Sets in Substance Painter.
Texture Sets in Substance Painter are derived from the materials set-up on the low poly mesh. A texture set operates similarly to a UDIM.
If you group (folder) a series of effects together for a particular effect, you can right click that folder and create a smart material from it. By doing this once per project (or more), you will build up your smart materials quickly. Alternatively, you can create smart materials in Substance Designer and import them into Substance Painter.