A song is not a string of bars. It's a form — sections of music (verses, choruses, bridges) that repeat and contrast. Drummers who hear form play differently from drummers who only hear bars. They know when to stay simple, when to fill, when to crash, and when to leave the bar empty.
Most pop and rock songs are built from a small number of sections — typically a verse and a chorus, sometimes with a bridge and an intro/outro. Each section is usually 4 bars or 8 bars long. Listeners can feel the section ending even if they can't count it; the music has built up an expectation that "something" happens at bar 8 or bar 16. That something is often a fill leading into the next section, followed by a crash on beat 1 of the new section.
The single most important drumming gesture in pop music is the crash on beat 1 of a new section. The crash announces "we just changed sections" — verse to chorus, chorus to bridge, etc. It's almost always accompanied by a kick under it (the foot reinforces the downbeat). Listeners interpret an unaccompanied crash on beat 1 as a section boundary even if no other instrument has changed yet.
Inside a section — the 7 bars between section boundaries, in an 8-bar phrase — your job is usually to not change. The temptation as a beginner is to add color, fills, kick variations every other bar to "be interesting." Don't. The song is interesting; you are the foundation. Sustain the same groove until the form tells you to change.
The exercises here represent a 16-bar phrase. The notation only shows specific bars — bars 1, 7, 8, 9 — because the rest are implied: bars 2–6 are the same as bar 1, and bars 10–16 are the same as bar 9 (with a possible second fill at bar 16). When you practice these, play the implied bars too. The whole phrase is the exercise.