上 is one of those swiss-army knife type of words/kanji. It has many uses and pronunciations, and can be attached to other words and compounds to modify them, as in the case of 使用上.
"Above" would be a very literal (and confusing) translation for this kanji in this case, but if you think of it as meaning "upon" (as in, "Precautions upon use of this product"), you can see it is kind of a not-so-distant cousin, and not too far off from Precautions for use, or Precautions when using. Learning when to ease up on the literal translations and be open to a translation or usage that is maybe not so intuitive, takes some time. So don't get frustrated at every instance like this. As I say, 上 has an unusually large number of possible readings and usages, despite its most obvious meaning of "up".
BUT, now that you have stored this particular usage in the long-term memory, you can read this phrase when it appears in any manual for any product. And you know that if 上 is attached to some verb, it probably means "when doing this verb", or "as you are doing this verb".
One step at a time. Its a marathon, not a sprint.