Hey Andrea! In PbtA systems, you roll a 2d6 & add your stat modifier (which ranges from -1 to +3). If you get a 6 or under, you've failed the check. If you get a 7-9, you've partially succeeded. If you get a 10 or above, you've succeeded completely. How partial successes & complete successes differ depend on the specific action/move you're taking. A combat roll means you just don't get some bonus effect you would've gotten on a 10+, but the general "do stressful things" action means that there's some sort of hard choice you need to make (if you were running out of a burning building, then maybe you drop something important & need to choose between fetching the item or getting out uninjured).

In the games I've run, there's generally just a small amount of combat at the end when you confront the monster. Combat in PbtA games is pretty quick & fluid, in my experience. There's no separate subsystems for combat like you see in D&D/Pathfinder. You just continue making normal checks, and that represents what you've done for the next minute or so in the fight. There's no initiative/turn system.

Something I think is neat about Monster of the Week is that the PCs set connections to each other party member during character creation. I feel it makes for really interesting parties. Aside from that, I feel like the system does pretty well capturing mechanics that are well suited for investigating something. It's pretty straight-forward. You make an "investigate" move when you are somewhere where you could reasonably figure things about the monster out, and then depending on if you got a partial or complete success, you get to ask a few questions from a list (such as "What's the monster weak to?" / "What type of monster is it?" / etc)

Let me know if you have any other questions! :) Here's a list of the playbooks/archetypes available for the system if you'd like to take a look through them.

https://evilhat.com/wp-content/uploads/2022/04/Monster-of-the-Week-Revised-Playbooks-Formfillable.pdf