The last part is the same as Part 2 except you have to play it with your left hand in a standard position, hitting ghost notes (simplified Hi-hat) with your third finger.
Two tricky parts are the fast hammer-on/pull-off line that starts at the same time as the snare hit with your right hand.
Work on this line by itself and slowly to get it right. Don't rush it as it could compromise your whole groove.
The slide part should be worked on focusing particularly on the hammer-on. Indeed, you have to hammer two notes at the same time and slide them.
The hammer-on is the key, it leads to a good sounding slide. Try to hit it hard enough to give it the maximum sustain needed in order to slide it foward and backward while keeping it sounding properly.