Learn Swedish: Hon går hem nu. - She is walking home now.

The base form of this verb is gå. It belongs to a group of short, one-syllable verbs that form the present tense just by adding an -r to the end. That is why it becomes går instead of having an extra vowel like regular verbs do.

The translation says "is walking". Why isn't there a word for "is"?

Swedish does not have an "is doing" (present continuous) form. The single present tense verb går covers both "walks" and "is walking". Because she is doing it right now (nu), "is walking" is the best English translation.

Why do we use hem here instead of hemma?

Swedish makes a strict difference between moving to a destination and being located there. You use hem (homeward) when there is movement toward the home, like in this sentence. You use hemma (at home) when you are already there.

I thought går meant "goes". Can it also mean "walks"?

Yes! In fact, when talking about people, går specifically implies moving on foot. If she were taking a bus or driving home, Swedish would use a different verb like åker or kör. So "goes by foot" and "walks" are the exact same word here.