okay so: i don't know where you're starting from, so that makes it a bit hard. i skimmed the MDN docs, and i think they're pretty decent, have you checked them out? You start here:
developer.mozilla.org/en-US/docs/L...
and then go to "introduction" and "using promises"
Asynchronous JavaScript - Lear...
If you have a fediverse account, you can quote this note from your own instance. Search https://bsky.brid.gy/convert/ap/at://did:plc:3danwc67lo7obz2fmdg6jxcr/app.bsky.feed.post/3llcbwnjy3k23 on your instance and quote it. (Note that quoting is not supported in Mastodon.)
