CFA Materials or Stalla/Schweser?? only, all, regarding, question, studying

gjcxc

Hi all,
I’ve read through numerous posts regarding study guides/materials and have one question: Do you use or advise using both the study materials from the CFA Institute AND a program study course (such as Elan, Stalla or Schweser), or do you use only one?
(I’m studying for Level I June).
Thanks!