I just did this same thing for the first time about an hour ago. Pretty simple. In addition to the linked instructions for creating the collections you have to enable metadata management.
In Calibre go to
Preferences ->
Import/Export ->
Sending books to devices and set metadata management to
automatic management. Then Calibre will automatically update the collections every time your Kobo is connected.
There is a fuller explanation on the wiki (
https://wiki.mobileread.com/wiki/Kob...nd_Collections) but it includes some extra stuff which it sounds like you're not interested in.