I’m interested in your thoughts on approaching the role as a GM.
I just answered a very similar question over on a another RPG forum so I will do a bit of crossposting...
If I were starting today:
I'd take 10 deep breaths and realize that tabletop is basically
telling tall tales with friends about their friends they created on paper
As a practice or warm up - try this idea out:
Recreate your own version of the "Last Supper" extra from ALIEN: COVENANT.
Have your friends playing the crew of the Montero share a story around supper before heading to hypersleep at the start of their mission.
Then they head to hypersleep and what happens next?
That's all there really is to play... just do 3 things:
1. Set the scene...
2. Let your friends describe what their friends on paper do in that scene/event/scenario/encounter/moment
3. Figure out what happens next using rules or what seems most fun
Then repeat.
For step 1, setting the scene - one of my sticky note GM screen reminders is:
"Describe from the player's senses" - what do they see, hear, feel, smell, taste ... or what "tingle" do their "spidey senses" get?
Try thinking of that last supper scene like that...
For step 2 - all you have to do is listen.
For step 3 - that is something you will work on forever as you play.
The more you get familiar with the system and setting, the more monsters, maps, NPCs, you create, the deeper you go into how to figure out "what happens next"
But just starting out - that's all you worry about - what happens next - based on what everyone has narrated so far.
Some great advice I've heard about how to be a GM comes down to being a fan of of your players' characters.
You are helping them tell their characters' stories in this situation.
When things go wrong, and they will, plan to "fail forward" - present the failure as a hook or option or opportunity to continue playing, but in a different plan or direction.
Think about ALIEN - the first plan was to catch it in a net and that fails disastrously ... leading to the airlock plan ... which fails.... etc.
Don't hesitate to take 3 breaths in the moment and give yourself time to mentally answer "in this situation - what would be the most fun for everyone?" ... then start talking.
It can get easy to get caught up in the moment and roller-coaster paint yourself into a quick corner.
From your description you've given yourself plenty of time for the game to take place - allowing for a pause to reflect before you go.
For some GM's - preparation is key: confidence comes from "knowing the path" before "walking the path"
If you have more time to prep - go through each location on the map and look at which rooms/encounters that location leads in and out from.
In that location, what could each of the players be doing?
The module has tons of notes... but for each note - what happens if that check or test is a success and
what happens if its a failure?
The failures are your opportunity to introduce the complications and setbacks that provide the challenges for the players to overcome.
But here's the really tricky part: You are not in conflict with the players.
Instead - you are the creator of opportunities for the players *to keep playing* - even a failure of a check or missing a clue is to provide a way to keep playing!
It's not up to you to solve the problems - you put the problems in front of them and let THEM try to solve them as they please... and then you figure the various things that could happen next from that and start setting that scene.
Don't worry about making mistakes - you will - we all do - even years or decades after first slinging dice.
We're human. Try to remind yourself this is fun with friends, not Shakespeare with a paying audience of drama critics.
It's O.K. to have fun, and be scared, and laugh, and slip and step back, and retry.
As long as you make it a party... its an event to spend time with friends and you've done them a solid by taking on the role of "fun host" by helping them tell their stories rather than trying to run your own.
I know that's a lot and its vague at first ... so here's a short bullet list reminder:
1. It's not Shakespeare! Take some deep breaths, relax and have fun with your friends!
2. Set the scenes.
3. Let them make their choices.
4. What happens next?
5. Be a fan / audience for the players' stories
6. When something fails - let it fail forward into the opportunity for a new plan or direction to have a chance.
I hope this helps somehow - please do keep asking questions - the world needs more GMs to facilitate having fun!
We live, as we dream -- alone. ~ Joseph Conrad