Indesign seems to support the addition of custom keyboard shortcuts for paragraph styles.
In the current version of Indesign CC the text box is there, but no matter what I try to type I can not set any values or even manage to type anything in the box.
Some online sources suggest to hold down a command key and a number key and that I must have a keyboard with a numeric pad, but since I don't have such a keyboard on my macbook I'm still stuck and this seems silly that it can only be set with the right keyboard.
How do I set a shortcut to something like âŒ˜+3 or whatever the syntax is?
I'm sorry to say, but it is not possible on a keyboard without a number pad.
You need to use the number pad numbers, for your shortcuts, not the regular ones.
You can still edit keyboard shortcuts through the Edit > Keyboard Shortcuts menu, but you can't assign Paragraph or Character Style shortcuts.
I've found that using the Paragraph/Character Style window(s) can be a fairly quick alternative. Open them under Window > Stlyes. This will allow you to easily pin them to your right-hand toolbar.
As you can see below, a window opens up with your styles listed. Move your cursor to the paragraph (or highlight the characters) that you want to change, then simply click the style you'd like to apply in the list.
I did also find a workaround (by installing a 3rd party app) here, but I never tried it
Unfortunatley it is not possible on a keyboard without a number pad.
Alternative 1: Use Quick Apply
I find it easier to use Quick Apply (Cmd/Ctrl + Return/Enter) and type a few letters of the style name or other command. There are a couple of ID commands that are not on menus or accessible through keyboard shortcuts, that aren't accessible via Quick Apply.
Alternative 2: Add support by installing a keyboard customiser
Otherwise explore installing a tool like this:
Use the app Karabiner (https://pqrs.org/osx/karabiner/). It can remap fn + number to fn + numpad number. With Shift+fn+1 you have Shift+Num 1. It works.