The Yogi and Reggie series of missions don’t become available until after you complete The Protector’s Arrival. All of them follow a similar pattern, where you get drugged and experience a hallucinatory trip, with the ultimate goal of each one being to find the duo and get your equipment back. They are rather short missions that aren’t too challenging.
You’ll notice from the get go at the start of Lost and Confused that everything, both animals and enemies, are tagged. Start by exiting the cave, being wary of the two bears inside, although they don’t seem to be aware of you. Also, the other thing you should notice is that you have no weapons at all, although you do have your healing syringes should your health need topped.
Anyways, continue to the first waypoint to find some macaques, which all disappear except for one (it will explode). Travel to the next one, avoiding the rhinos on the way, as well as the rhinos that show up at the waypoint. The third spot will have a few enemies, along with a bear or two, which you might want to avoid. When you get to the cave, you’ll find the pair of smoked up fools and will finish the mission.