This is an open hi hat groove practice exercise with short drum fills every 4 bars to keep it interesting to play.
There are a few ways to play the open hi hat. You can open it quite wide and hit on the top or the edge, or open it a couple of cm wide for somewhere in the middle, or open it a little bit to get a nice sizzle. The screw underneath the bottom hi hat cymbal can generate more of the sizzle sound when it is screwed tighter, creating an angle on the bottom cymbal.
Related: For some easier open hi hat exercises, try these: Off Beat Open Hi Hat Grooves