“Every other…” means each alternate. If I say “My husband shaved today. He’s not going to shave tomorrow, but he’s going to shave the day after.” It means that my husband shaves every other day; he’s skipping every second day.
Please write on every other line.
It means: Write on the first line, do not write on the second line, write on the third line, and so on.
• She visits her parents every other week.
• Please put your signature on every other page.