Damn, it's times like these I wish this weren't a Maori traditional agriculture site or I'd join up with you. I don't know if you're playing quickplay or low elo, but that sounds fucked up.
How it's supposed to work is that, outside of a specific composition (6 people on comms, higher elo), 2/2/2 is a safe bet. The basic gameplay resolves around sight-lines - the job of the tank is to take space up to the corner of the sight-line where the healers can still see them from the back.
As a tank, you have a couple of jobs, but your primary job is to make space, moving forward and taking area control. Some tanks, like Venom or Hulk, want to dive and make a distraction in coordination with a dive or harassment DPS. Other tanks, like Magneto and Strange, provide cover for their DPS and Supports in order to poke or teamfight to build up ult charge. Further tanks are somewhere in the middle, themselves an aggressive force that the opposite team needs to deal with or their line breaks.
DPS is more varied, but basically wants to work with their tanks to take space and hit the opponents, while defending their own supports. There's different game plans, but the basic rock paper scissors resolves around poke/dive/teamfight comps. Poke beats teamfight beats dive beats poke kind of deal. (I might be wrong but that's how it goes in my experience).
Supports actually have probably the most internally varied game plans, but their singular job is to keep the team alive, and to provide accessory value to their team. Playing C&D for a day really actually taught me how much they should be the shot-callers and how important sightlines are. If you go around a corner, the healers can't heal you if they can't see you. This goes for everyone, and the supports want to be as far in the back as possible. What that means for you as a tank is that you sometimes want to be looking back and making sure your supports are still there, can still see you, and aren't getting molested by Black Panther. Ideally, in a perfect world, you have perfect comms and everyone calls out information. Support tells you how far they can see and if you leave their sight lines.
1) Supports call out sightlines and tell tanks where they can see safely.
2) Tanks move up to the edge of that sightline safely.
3) DPS plays their gameplan. They should aim to create value by forcing the other team to spend resources while preserving their own resources. I don't think I'm good enough to explain each DPS gameplan, but from what I gather Divers want to coordinate with a dive tank to get picks. Harassers want to draw fire from tanks by attacking a flank and then leaving safely, getting picks where they can. Teamfighters want to generate value by grouping up and deathballing through the map. Pokes like Widowmaker want to critically endanger enemy squishies enough for their tanks or other DPS to take them out, etc.
4) No plan survives first contact with enemy.
5) Rinse and repeat. Tanks move up to next sightline, healers keep them full, and DPS protects their supports/kills enemy squishies and gets picks.
6) Ults happen. These have their own little metagame, but the idea is you deal with them as they come. Sometimes you get pushed back because of a strong ult, or the tides of battle get turned over, etc. There's a rock paper scissors to them, like using healing ults to block damage over time ults, but can't block instant kill ults, etc. It's kinda just a matter of learning what and when.
Other than playing some games that's the best I can do, hope it helps.
