How do Projectile and Las weapons work on shields in Dune?

I'm reading through Dune right now and I'm a bit confused on the specifics of the weaponry in the book. It never seems to go into great detail and it makes some of the action scenes a bit hard to picture.

What I understand is that las guns are like plasma or lasers or something? And body shields stop projectiles, but cause massive explosions when they come into contact with las weaponry, correct?

I've also played Dune 2000, a Real-Time Strategy game released in the late 90s, set in the dune universe. Infantry use "machine gun" like weaponry, and tanks use projectile explosives, but it uses a similar engine and very similar units to the previous games the company (Westwood) has created (infantry almost identical, tanks similar too). So, I'm not sure if this is an accurate depiction.

It would also be handy to know what kinds of weapons they're using. Are they automatic? Semi-auto? Do they have long rifles for sniping? Is there variation at all? Do they have melee weapons? The Fremen are depicted as amazing fighters, but also somewhat poor

hoping someone can explain in better detail