Some words in Norwegian have multiple meanings, and sometimes it's almost impossible to distinguish for someone who isn't fluent.
One particular example is the word "om"
Depending on where you first learn the word, you probably recognize it as meaning "about" for example in the sentence "What do you think about...?"
"Hva tenker du om...?" (literally meaning "what think you about...?")
But then maybe you come across the phrase "om du aldri prøver, du aldri vinne" (if you never try, you never win)
So now, not only does "om" mean "about", it also means "if". This would not be so bad if om didn't also mean "on":
"Det er om bordet" (it is on the table)
Fortunately, this is a pretty unusual thing to say, as a preposition (words which define the location of something eg. in, on, under, around) it would be more common to use the word "på" for this scenario in the sentence "Det er på bordet".
To further confuse the situation there is also another word for "if" - "hvis". At the beginning of a sentence, these terms - hvis and om - are virtually interchangeable. You could say "Hvis du vil" or "Om du vil" to begin a sentence with "If you want". however, it is important to note that "hvis" is rarely used in the middle or end of a sentence (not that any proper sentences end on the word "if" in either language). For example, you cannot say "Jeg ble spurt hvis jeg hadde en katt" (I was asked if I had a cat). The correct way would be to say "Jeg ble spurt om jeg hadde en katt"
Om is just one of numerous words that are either the same and have different meanings, or are spelled or pronounced similar but have different meanings. The word in Norwegian for "meaning" is "betydning" and as you learn more and more Norwegian you will quickly discover that there are many homonyms (words with different meanings) in the language. Unfortunately, the only way to learn this is to learn the meanings and practice using them in different sentences, so, good luck.