Learn Farsi: من الان دارم از خیابان رد می‌شوم.

It uses the helper verb dâram (the "I" form of "to have") and the main verb mi-shavam at the end. In Farsi, combining the present tense of dâshtan with a present indicative verb creates the "I am doing something right now" meaning.

Why is the helper verb dâram separated from the main verb rad mi-shavam?

In the Farsi present progressive structure, the helper verb (dâram) usually comes early in the sentence, right after the subject or time word. The main verb (rad mi-shavam) always stays at the very end. The object and prepositions go in between them.

Why do we use the preposition az (from) to talk about crossing a street?

The compound verb for "to cross" or "to pass" is rad shodan. In Farsi, this verb requires the preposition az. You are literally saying that you are passing "from" or "through" the street.

What is the infinitive form of the main verb here?

The infinitive is rad shodan, which is a compound verb meaning "to pass" or "to cross". Here, we see the "I" form in the present tense: rad mi-shavam, where mi- is the present tense prefix and -am is the personal ending for "I".