Quality diet, clean water. There are many tips and tricks to trigger Plecos spawning. Sometimes wild caught Plecos can be more picky that f1s, and sometimes they are easier. I would add some good currant and let them adjust to the tank, feeding once a day. Once they are comfortable I would increase the feeding to twice a day making sure at least one of the foods is very high in protein. Make sure your caves are suitable and it doesn't hurt to put a price of driftwood on top the the caves. Start out with a setup like this and leave the fish alone. Try to make sure your filtration is high enough that you arent changing water too often. After a few months of you don't see any interest then you can start making small changes to trigger a spawn