Most SIDE OPS are quite easy and short, however there's 157 of them so this takes a while. They're also farily straight-forward and the location is usually marked. So there's no dire need for a guide. But! It's always nice to have one, to check what you still have left to do. So here is a list with all SIDE OPS with a small description and useful information. All credit to vinheim!
https://gamefaqs.gamespot.com/ps4/718564-metal-gear-solid-v-...The Target Practise SIDE OPS are a bit tougher, there's a time limit and some are hidden. So the best way for those is to watch the following video and pause and play along so you won't miss any. Especially the R&D platform is tricky.