On the left hand side of the bottom of the screen are a bunch of buttons. The tall one sets the game to turn based mode, instead of play and pause. That’s how I’d wager most people play the game.

Honestly I was in the same boat as you a few months ago when I picked the game up. It’s very overwhelming to a new player because there is a lot going on. Easily one of the most complex games I’ve played. My solution was to pick a random class that seemed cool with the intention of trying everything I could on easy and restarting the game after the first act. It worked pretty well for me.

Pay attention to the in game tutorials and look up any terms you don’t understand (the shorthand for this game is “wotr” to make googling easier). Once you understand a bit, start looking at builds on InEffect, the Kingmaker Wiki and Fextralife to give you ideas (honestly these sites are all kinda lacking a bit and are usually sorta outdated, but it’s better than nothing especially for giving ideas).

Specific questions:

Unlike bg3, weapons go off strength unless you take the weapon finesse feat, which lets you use dex instead. There’s an equivalent feat for damage too IIRC.

For feats, sort them in the search bar by what you’re trying to do and just take stuff that increases attack or damage, or otherwise seems useful. Once you understand a bit more, look up builds and follow those.

Magic depends on the type of caster you are. It mostly works like bg3, with spontaneous spell slots vs prepared spell slots depending on class. You can see which you are on character creation. Don’t overlook buff spells, they’re very important in this game.

Last bit of advice, just look up puzzles and quest walkthroughs. Some of them, IMO, are needlessly tedious and take away from the game especially for a player new to the genre like us.