How to take stool sample??

Hey y’all, I’m doing my first stool sample snd it came with three containers and zero instructions. I know the big bucket is just to catch the poop but then do I just… use one of my non sterile spoons at home to scoop it into the two small containers? Why are there two? How much do I put in the yellow one, because there is no fill line? Thanks for the help, this might be a silly question but I just don’t want yo mess it up and I’m not sure why they gave me zero directions/clarification…