I'm still learning the basics of norsk and prepositions. I saw in that post "Jeg er glad i deg!" translates as "I am fond of you!" In what I've been reading so far, "i" translates as "in." Is it also "of?" Are they the same in norsk?
This is a really good question. When we learn new languages, we often translate unknown or new words into ones we are already familiar with in a known language. The problem with this is that different languages were formed by people of different cultures, time periods, etc and don't translate 1 to 1. So for simplicity's sake, "i" translates to "in" and "av" translates to "of." Unfortunately "i" and "in" aren't always used interchangeably in translations (that would be too easy!), and there are some exceptions. One of these is "glad i deg."
Norwegian has some phrases and words that always marry with a specific preposistion, even if we wouldn't use the same one in English, and it's easier to memorize these (or use them frequently so you start to associate them together). Here is a good resource that has phrases with preposistions - it's a pdf so I hope the link works, if not, google 94 uttrykk med preposisjoner.
Prepositions can be really confusing, but try not to feel to frustrated by them. Native speakers mix them up all the time, and different dialects might use different preposistions in the same context.