I found the following video guide helpful in describing what is needed for this achievement. Credit goes to PAXTAG on YouTube for the commentary.
Basically you need to cook 15 items in a single go using the cooking pot located within any outpost or den. One of the easiest way of doing so is collecting or purchasing at least Flour x15 and Coconut x15 and using those ingredients to cook with.
This is found in story mode > Round 3A on the fourth level.
From the start of the level, interact with the caveman on the left a few times and then interact with the caveman in front of the "Gameboy" on the right to worship it. Then interact with the "Gameboy" and complete the jump mini game which will start up the running sequence. You will need to allow one of the cavemen to advance ahead of you prior to the last jump so he can give you a high five as you try to clear the final jump.
This is found in story mode > Round 2C on the 3rd level (i.e. the one where everyone wants to lick you). From the start of the level, simply go left into the bathroom and interact with the guy leaving the stall.
This is available in story mode > Round 2A on the office tower level. From the start of the level, head right to the elevator and select floor 2F. Then, head left from the elevator into the office and select the sleeping guy to kick him.
Make sure you have the rocket launcher equipped in your inventory, then select it from the weapon wheel.
Best way to get a double kill is to target an occupied enemy vehicle, which usually have at least a driver and a gunner. You can wait by a major road and one should drive by eventually. Or if you’re attacking a base and reinforcements are called, you can target a car full of enemies as it arrives.
Press and hold LB to aim the launcher, then fire with RT.
You can discover bivouacs by stumbling across them or looking for the smoke-like signals indicating where they are, but I think the easiest way is by looking for the intel icon (the little “i”s) and selecting a nearby bivouac whenever that’s an option. (Instead of a weapon blueprint, collectible, etc.)
No matter what this will take some time to get, but easily accomplished during a playthrough.
This was a bit tricky because I tried to be more sneaky my first few attempts. It can be difficult to find enemies while you’re still in the air.
A more foolproof method is to be aggressive and parachute right into the middle of an enemy base, so you have a number of readily-available targets to engage as soon as you land. You can always lower the combat difficulty if that helps.
You’ll earn 100k credits pretty easily by completing missions, opening crates containing credits, and taking them off of fallen enemies. No need to go too much out of your way, you’ll get enough credits eventually so long as you put the time in.
I recommend spending at least some of those points on vehicles. It’s nice to have some options available at bivouacs, like an attack helicopter, armored car, dirtbike, etc.
The 8 missions need to be done in one *real life* day, not an in-game day. This isn’t nearly as time-sensitive as you might think.
The available missions reset every 24 hours. If you look at the available faction missions in the menu it will show you how many hours/minutes are left until the daily reset.
As long as you have an hour or two before the reset you should be able to knock the 8 missions out. But if the reset is coming up soon, just wait for the clock to restart before starting the first mission.
The carillons are spread across the map, but are all fairly accessible. Between fast traveling and flying a helicopter you can reach them all no problem. You don’t need to interact with them, standing near them for a few seconds will suffice.
This video (credit to Gaming with Abyss) shows the locations better than I can explain them: