Learn the chart, then look up
Use the chart to track the arrangement while your ears follow the band.
A chart is useful when it tells you what you need to know in time to play it. It may show chords, melody, drum notation or only section names. Before practicing from it, find out which version of the song the band will use and what the symbols mean.
Mark the changes that matter
Listen once for the form, then again for drum entrances, stops and transitions. Count the bars in any section you keep losing. If the band shortens an intro or repeats a chorus, update the chart to match.
A number chart mainly describes harmony unless rhythm and form details are added. A slash chart may leave the groove to you, and a written drum part may specify individual notes. Do not assume a row of chord symbols tells you where every drum hit belongs.
Practice using the page
For an example form, write "verse 8 bars, chorus 8 bars, verse 8 bars, ending cue." Play a familiar 4/4 groove while counting the bars quietly, and glance at the next section before you arrive there. This is a reading exercise, not a supplied song arrangement.
Then have a bandmate cue a repeat or ending using the signal agreed at rehearsal. If you lose the place, add a clearer section marker or practice that boundary again. Keep the chart positioned so you can see the leader without turning away from the kit.