What's the difference between them?

I know thrust reversers is F2, and they slow you down pretty quickly. Some planes (jets) even show them working.  I always hit F2 as soon as I hit the ground.

Then some, heavy mostly, have autobrakes.  Set them to max and as soon as you hit the ground the brakes kick in.  So do I need to hit the brake "pedal" (Fire button) too?  I usually hit this one, too, as soon as I hit the ground.

Now I have a few military jets that have a "speed brake" button and a big panel pops out behind the pilot.  What's the purpose of this?  Is there a key command other than the "speed brake" button on the panel?

Spoilers, I think, are the equivalent of speed brakes but they pop up on top of the wings in civilian jets.  I haven't ever seen them in action.  When would I use them and is there a key command for them?

I also see that some ac have throttle commands to "arm" and "engage" spoilers.  When I'm landing there's a little too much happening to "engage", so I just land with full flaps, reverse thrusters (F2) and brakes (Fire button).  This has never presented a problem (running out of runway).

One more thing - if the aircraft.cfg says reversers=0 can I just change it to 1 and get reversers?

Usualy the spoilers are even used in the air when descending to slow down big heavy metal planes like the 747 or 777. Due to the small air turbulances they make in the rear side of the wing the plane will slow down without shaking or stalling..!

When I land I start with the spoilers fully up and full reversers, and when I reach around 60-50 knots I drop the spoilers and return the engines to idle and start using the brakes...

But if you use them all together the plane will stop in a pretty small distance after getting the passengers off their seats..!!

Therefore I don't recommend using the reversers, spoilers, and brakes together when landing.

I've been in a plane b4 and saw them in action, and I think the mentioned way is the best way to land.!

NOTE: if you want to use spoilers in the air, make sure you don't raise them more than 40% or you'll get you yourself in a big trouble!

This is the way I do it. Exactly when the wheels hit the ground, I deploy the speedbrakes manually. I wait until the front nose touches the ground, and I apply minimal reverse thrust (if the runway is long enough), or full reverse thrust. I tap the brakes every1-2 seconds in intervals. In real life, reverse thrust wares out the engine over time, and applying too much brake will ruin your tires too.