Steve Gadd based Hihat Groove
As you see in the video the stroke is based on a single stroke in 16th notes with flame on beat 2 and 4. First try the snaredrum preparation to get used to the left hand which is playing 3 16th notes in a row with the middle one accented. Once you get used try the hihat grooves. You will see that these are very nice grooves to play and improvise with it.