I know there are a lot of new folks coming in who are either new to Pred/MOBAs in general. Here are some simple tips to help you in each role. Feel free to add more tips in the comments.

DUO LANE: As carry your mission is to farm. There is literally only one viable build for ADC right now and that's full crit all day with Imperator. Get that dash item as your active because movement is never bad. In the laning phase stay on the OUTSIDE of the lane, let your support be in between you and the jungle, if there is a gank coming in there will be more time to react. Use your wards in tandem with them, make sure all 3 paths in are warded as much as you can. Don't overextend, poke if you feel you can, but focus on last hitting. In terms of wave management, you don't want to be auto-attacking minions the whole time but you also don't want them under your tower (and harder to last hit). Try and keep the wave just on your side of equilibrium. Come late game you either need to be split pushing while your team is grouping, or moving with them to fight, or take objectives. When in doubt just move with the group and farm wherever possible. As support your role is a lot harder. Your primary job is to keep your carry alive. If you're ranged you can play the poke battle but pulling minions around can throw off your adc. If you're going to trade make sure you get the better end of the exchange and make sure you save enough mana for key spells if you get ganked. If you are melee than just... live. Don't get crazy, don't get aggro, just live. It will feel weird and boring. Help your carry manage the wave, get your crest stacks, and live. It will feel wrong but it is absolutely what you are supposed to do. If your carry goes the first 10 minutes of the game without dying you've done your job. Come mid/late game you are allowed to leave your carry if they're off solo farming, your job then becomes to support the team as much as you can. This will depend a lot on what kind of support you're playing, but often you will be the key follow-up off of your jungle or offlane.

SOLO LANES: I will group mid and offlane together here because they function pretty similarly, with the biggest difference being mid is often a ranged caster and offlane a melee bruiser. The concepts are the same, bully your opponent as much as you can without sacrificing last hits. If you feel you aren't winning trades that's totally fine, back up, play passive, focus on last hits and managing waves. Your role is to not get ganked by the jungle and farm. Come mid/late your role will change (offlane's often are ones to engage team fights, mids are ranged burst heroes who can help execute ganks etc). But overall if you don't feel comfortable going for solo kills, don't! Keep an eye on your jungler, if you see them heading your way let the wave push to your tower and make it easier for them to gank your opponent.

JUNGLE: Start on red buff. Clear your other two camps, look to harass mid, try and make them burn their flash, then go to blue, do the other side, then look to gank either mid or carry lane. Ward key jungle paths and fangtooth come early/mid-game, and once you get your ult and your first item you can generally solo it (as heroes like Khaimera it's super easy). You just roam, farm, pressure, and try and get kills but if you don't, don't bother to tower dive. Take HP, make them back, and help your other Lanes win. You will never be top damage but that's fine, your job is just to be a nuisance and make the enemies constantly nervous in their lanes.

Overall you should be warding like a maniac regardless of role, and DON'T OVER EXTEND. If you're pushing up to do damage to a tower and it feels to easy. It probably is. Unless you can see all your opponents on the other side of the map, do some chip damage, then back up. It's always better to play it safe than feed your enemies kills.

Hope this helps.