Returning is self-explanatory, but I'll attempt to go over it in-depth. It basically returns information and is usually used in functions, but it can be used in several other instances but that's more advanced.
For example, look at this example code:
1 | function addNumbers(number 1 , number 2 ) |
2 | print (number 1 + number 2 ) |
See, that will print out 7 because of the parameters we set which are 2 and 5.
However, what if you wanted to get that information and use it to change a text label? It's quite simple actually:
1 | local text_label = script.Parent |
3 | function addNumbers(number 1 , number 2 ) |
4 | return number 1 + number 2 |
7 | text_label.Text = addNumbers( 2 , 5 ) |
See, you can actually use that data out of the function and it is very helpful, note that this isn't the only thing you can do with it. The options are endless!