Complex sentence: They both can laugh a lot together and Gregor gets a little bit astonished sometimes when Luise doesn't know how to deal with the (for him) easiest things, such as making coffee or knowing that a vacuum bag needs emptying, otherwise it will burst.
Split into simpler sentences: They both can laugh a lot together and Gregor gets a little bit astonished sometimes when Luise doesn't know how to deal with the-for him-easiest things. Like making coffee or knowing that a vacuum bag needs emptying, otherwise it will burst.