There's not an official licensing rule at this time, pretty much any imaginable usage of these texture assets in other work is fine short of reselling/redistributing the package as is.
You can use the textures & decals as a resource in 3d renders, game levels, VFX shots with no particular limitation or constraint on such uses.
As long as you're building something new using them instead of just taking the package unmodified and trying to resell it.
Attribution's not required. You can modify or not modify textures as needed for your particular scenes. There's no particular limit on how many are used in a derivative work.
No limitation on number of computers an individual can load it on or on number of creative projects using it as a resource. The goal is to keep things fairly open and basically ask for common sense to be applied.