Lambor's Hold

I think Narissa is the only one of you to have darkvision, so with her still asleep, this is all you can tell without a source of light.

Narissa is taking one bed. Who else of you is sleeping in a bed and who is on the floor?

I'd assume Belathor is on the floor as a late comer, probably curled up a little too close to Arphaxad.

I think Taz would've taken the second bed if it was still free when she reached the room. She does have darkvision though, as a half-elf.

Unless the beds are tiny cot like things we might get 2 to a bed.

Alright, let's go into combat here. Belathor can cast on his turn. I will say you all (except Narissa) are awake now and able to get to your feet and draw your weapons before combat starts. I will roll Init for all of you as well as the enemies. S1/S2 are the swarms, C1/C2 are the centipedes. With your tokens, it should be clear who is who.
On your turn, feel free to update the map if you know how otfbm works. Otherwise, just tell me what point on the grid you're moving towards and I will move you. Quarters are pretty cramped but you can move past each other without need for a roll.

We will go with regular inititative here so everyone acts on their turn. If that seems to drag too much in PBP, we might think of another way for the next combat.
Narissa will wake up on her turn. She is prone until she acts to get up.

That is a total of way too much damage on Belathor who goes down to 0 hit points immediately as he is swarmed by both the swarm and the centipede.
Auras takes six points of damage and will need to make a Constitution saving throw.

With the creature's attacks finished, it is then also Auras' turn

I don't think you have to make an attack roll for Dissonant Whispers, but even if, that would hit. The Centipede succeeded its save, so it takes half damage (3) and doesn't have to flee.

Taz is up next, no change to the battlemap

Narissa is up next, current battlemap in blue's post

If you had to make an attack roll, you'd use the spell attack modifier. For Frostbite, you don't as it requires a saving throw. It's usually (but I don't know if always) either/or
Either way, it's a success and the centipede failed its save

Centipede 1 is dead, Swarm 1 has lost some cohesion.

It's Arphaxad's turn.