>>949723
smug/tg/ has a teaching thread that's meant for newbies to ask questions. Worth a read.
Otherwise, pick a system:
Either an OSR[Old School Roleplaying] because it's where the hobby started and tends towards greater rule simplicity and more creative GMing not a problem if you're the GM either, as long as you've been reading/watching media of the genre the system is set in, or rules-light stuff like Ryuutama or MaidRPG are probably good choices. As for OSR, depends on the genre you want: Astonishing Swordsmen & Sorcerers of Hyperborea if you're into Sword and Sorcery, Swords and Wizardry for classic fantasy, Stars Without Number for Science Fiction, Adventurer Conqueror King for classic fantasy with a focus on long campaigns/endgame mechanics (roughly speaking, all of the above have supplements that can change the genre)
If you happen to be the GM, pick one of the introductory scenarios that are included in or otherwise attached to the rules, they're simple and easy to run. Then you just have to find 2+ friends to play with.
While you're at it, also grab the Mythic GameMaster Emulator, a system compatible with all Pen and paper rpgs that allows you to play on your own/with only two people by emulating a GM. It's invaluable for testing out your knowledge of the rules and developing your presentation skills before unleashing yourself on a group of players by enabling you to play through the scenario by yourself first.
As for finding groups, if you can tolerate soyboys, roll20 forums are the easiest solution for online play. /tg/ also had a gamefinder thread, but the split between 8/tg/ and smug/tg/ basically killed both.
If you want IRL groups, you'll either have to find friends you can talk into this, or look up "[Nearest big city] RPG", ""[Nearest big city] Pen and Paper" etc. There's often forums or websites dedicated for local people to find groups.
If you don't want to play D&D5e (which you don't because it is irredeemable trash), be prepared to be the one GMing though. People often need to have good taste beat them over the head before they notice that they're eating shit.
