Antaŭ ol vi transiras la straton, rigardu ambaŭflanken.

Antaŭ ol means before when it introduces a whole clause with a verb.

• antaŭ by itself means before or in front of
• ol is part of the fixed expression antaŭ ol, used before a finite verb

So:

• Antaŭ ol vi transiras... = Before you cross...

If there is no full clause, Esperanto can use just antaŭ:

• Antaŭ la vespermanĝo = Before dinner
• Antaŭ transiri la straton = Before crossing the street

Because Esperanto often uses the present tense in time clauses like this, just as English does.

In English, you say:

• Before you cross the street...

not

• Before you will cross the street...

Esperanto works similarly:

• Antaŭ ol vi transiras la straton...

This is natural for a general instruction. Transiros would sound more tied to a specific future event, and is less natural here.

Transiri is built from:

• trans- = across
• iri = to go

So transiri literally means to go across, and in normal English that is simply to cross.

• transiri la straton = cross the street

This kind of word-building is very common in Esperanto.

The -n marks the direct object.

Here, la strato is the thing being crossed, so it becomes:

• la straton

Compare:

• Mi vidas la straton = I see the street
• Mi transiras la straton = I cross the street

In both cases, la straton is the direct object.

Rigardu comes from rigardi, meaning to look.

The ending -u is the Esperanto verb ending for commands, requests, instructions, or wishes. So:

• rigardi = to look
• rigardu = look

In this sentence, it gives an instruction:

• rigardu ambaŭflanken = look both ways

Because in Esperanto, commands usually do not need the subject pronoun.

So:

• Rigardu! = Look!

is perfectly normal.

You can say vi rigardu, but that sounds more emphatic, as if you are stressing you in particular. In an ordinary instruction, leaving out vi is the most natural choice.

Ambaŭflanken means to both sides, or more naturally in English, both ways.

It is built from:

• ambaŭ = both
• flank = side
• -e / -en style adverbial form related to direction

So the idea is: look toward both sides.

In everyday English, the best translation is usually look both ways.

Because Esperanto very often forms compounds by joining meaningful parts into a single word.

So ambaŭflanken is a compact compound meaning something like in both side-directions.

This is normal Esperanto style. Compounds are extremely common, and learners often need a little time to get used to reading them as one unit.

The final -n here adds a sense of direction.

• ambaŭflanke = on both sides
• ambaŭflanken = toward both sides

Since looking involves directing your gaze, ambaŭflanken is the better choice here. It suggests turning your attention left and right.

Yes. That is also correct and very natural.

There are two common ways to say this idea:

• Antaŭ ol vi transiras la straton, rigardu ambaŭflanken.
• Antaŭ transiri la straton, rigardu ambaŭflanken.

The second version uses the infinitive transiri instead of a full clause. It is a little shorter. The version with vi transiras is more explicit.

Because the first part is a subordinate time clause, and the second part is the main clause.

• Antaŭ ol vi transiras la straton = subordinate clause
• rigardu ambaŭflanken = main clause

The comma helps separate those two parts clearly. This is standard and easy to read.

Yes. You could say:

• Rigardu dekstren kaj maldekstren.

That means Look right and left.

It is slightly more explicit, while ambaŭflanken is more compact and idiomatic for both ways. Both are understandable and correct.