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

Answer

The las guns shoot laser beams, and when they hit a body shield, or ship shield the result is something close to the level of an atomic bomb going off. the projectile weapons are similar to guns we use today, in which shields stop the kinetic force of the bullet.

No one really uses las guns anymore to begin with, because they cost a lot of energy and are not very efficient.

Instead because of the invention of the personal shield people have gone back to fighting with short swords/daggers as its a refined ability to be able to wield your weapon slow enough to penetrate the shield's kinetic barrier. People also typically don't use las guns, because of the resulting explosion killing both users.

Las guns are a remnant of earth 20,000 years or more before Dune. 10,000 years before Dune, during the machine war, they had already stopped using las guns as they were simply too inefficient, leading to the widespread use of projectile guns again, and the creation of the personal shields.