Dashes are tricky. Here’s how I learned it:
Single dash (hyphen) used to hyphenate words shout-out
Longer dash (en-dash) used to give number and date ranges 2017–2019
Double dash — the width of a letter M, (the em-dash), this is the Swiss Army knife of punctuation marks and can be used to replace the semi-colon in certain circumstances. Not all.
If you make these in Word the software creates them automatically.