When I teach HeroQuest Glorantha to RPGers who don't know a thing about both the system and the setting, here's what I usually do:
- I give them a short introduction pitch to Glorantha: Sartar & the Lunar Empire, how the gods and of the myths influence the setting, and the importance of the Runes.
- I hand them out a blank piece of paper and we do character creation as we go. I try not to get too much into details, and if necessary, I even give up on the flaws.
- When their Runes are chosen, I help them chose their god, which usually creates a little, useful discussion on the deeds of such and such deity.
- Usually, midway through character creation, when it's time to distribute the additional points, I quickly explain them how the rules work, and I simulate a situation with them (like a social conflict, a brawl, etc.). It helps them get a hang on how bumps and masteries work.
- If they don't know what kind of abilities / breakout abilities to create, I tell them not to bother, as we'll see that during the game.
- For the adventure, I learnt the hard way that even the simplest adventure could sometimes confuse my players, especially when HeroQuests are involved. requiring your players to remember a myth, or to learn its details, and eventually to reproduce them, could turn them off completely. Basically, some could get lost in all those details, feel like they are too railroaded, have no agency whatsoever, and end up not knowing what to do in the end as they were not having fun. So now, I'd rather send them on a HeroQuest by giving them elements of the myth step by step, as they move forward (an action may trigger a specific memory in a character, an NPC met during the HeroQuest challenges them with a riddle whose answer offers them some direction, etc.)
To finish, I'd say that when I run games of HeroQuest Glorantha, character creation and the adventure are both simplified and "as-we-go". Listen to your players, listen to what they like. If they come from a d20 background, offer them a nice taste of Glorantha and the system with an adventure that can both challenge their roleplaying habit and feel like home.