Až se vrátím z práce, podívám se do zrcadla a dám si sprchu.

Here až means when / once, specifically with a future sense: once I get back from work...

A very useful rule is:

• až = when/once for a future point
• když = when in a more general sense, often for repeated situations, present facts, or past events

So:

• Až se vrátím z práce... = When I get back from work...
• Když se vracím z práce... = When I’m coming back from work / When I come back from work in a habitual sense

In everyday speech, Czech speakers do sometimes blur this a bit, but for learners, až is the safest choice for a one-time future event.

Because in Czech, perfective verbs often use their present-tense forms to express future meaning.

That is exactly what is happening here:

• vrátím se = I will come back
• podívám se = I will look
• dám si = I will have / take

These are not present-time actions here. They are future because the verbs are perfective: they describe a completed whole action.

This is very different from English. In Czech:

• imperfective future usually uses budu + infinitive or a special future form
• perfective future uses the present form

So:

• budu se vracet = I will be coming back / I will come back repeatedly
• vrátím se = I will come back once, as a completed action

Because vrátit se means to return / to come back, while vrátit without se usually means to return something.

Compare:

• Vrátím se domů. = I’ll return home.
• Vrátím knihu. = I’ll return the book.

So the se is not optional here. It is part of the verb vrátit se.

Podívat se is the normal verb meaning to look or to have a look. In this case, se is simply part of the verb.

Czech has many verbs that are naturally used with se, and English often has no direct equivalent for that little word.

So:

• podívat se = to look
• dívat se = to look / be looking
• podívám se do zrcadla = I’ll look in the mirror

You should learn podívat se as a whole unit, not as podívat + se with a separately translatable se.

This is because se is a clitic in Czech. Clitics tend to go in the second position in the clause.

So in the first clause:

• Až se vrátím z práce
• the first element is Až
• so se comes right after it

In the second clause:

• podívám se do zrcadla
• the verb podívám is first
• so se comes after that

This is why Czech word order can feel strange to English speakers. The position of se is governed less by English-style logic and more by Czech clitic placement rules.

It is genitive because the preposition z means from / out of and normally requires the genitive.

The base noun is:

• práce = work

After z, it stays:

• z práce = from work

That may look confusing because práce is also the dictionary form, but in this noun the genitive singular happens to have the same form.

So:

• jdu do práce = I’m going to work
• vracím se z práce = I’m returning from work

Because Czech uses the expression podívat se do zrcadla for look in/into the mirror.

The preposition do takes the genitive, so:

• zrcadlo = mirror
• do zrcadla = into the mirror

English says look in the mirror, but Czech thinks of it more like look into the mirror.

Other prepositions would change the meaning:

• v zrcadle = in the mirror as a location, for example Vidím se v zrcadle = I see myself in the mirror
• na zrcadlo would mean onto the mirror / at the mirror surface, which is not the normal phrase here

So podívat se do zrcadla is the standard idiom.

Because sprchu is accusative singular, and it is the direct object of dám si.

The base noun is:

• sprcha = shower

In the accusative singular, it becomes:

• sprchu

So:

• dám si sprchu = I’ll take a shower

This is a very common pattern with feminine nouns in -a:

• káva → kávu
• večeře stays different in its own pattern
• sprcha → sprchu

Literally, dám si is something like I’ll give myself.

But in real Czech, dát si is a very common expression meaning:

• to have
• to take
• sometimes to treat oneself to

So:

• dám si kávu = I’ll have a coffee
• dám si pauzu = I’ll take a break
• dám si sprchu = I’ll take a shower

The si is the short dative form of sobě (to oneself / for oneself). In many expressions, it adds the sense that the action is done for oneself.

Yes, dám si sprchu is natural and common.

Other possibilities include:

• osprchuju se = I’ll shower
• půjdu se osprchovat = I’ll go take a shower
• budu se sprchovat = I’ll be showering

The differences are mostly about style and aspect:

• dám si sprchu sounds very natural and conversational
• osprchuju se is also fine, but a bit more directly verb-based
• budu se sprchovat focuses more on the process, not just the completed act

So in this sentence, dám si sprchu is a very idiomatic choice.

Because podívám se is perfective, while dívám se is imperfective.

That means:

• podívám se = I’ll take a look / I’ll look once
• dívám se = I am looking / I look / I watch

In this sentence, the speaker means a single completed action after getting home, so podívám se fits better.

Compare:

• Podívám se do zrcadla. = I’ll look in the mirror.
• Dívám se do zrcadla. = I’m looking in the mirror.

So this is mainly an aspect choice.

Because Czech usually does not need subject pronouns when the verb ending already shows the person.

For example:

• vrátím se already means I will return
• podívám se already means I will look
• dám si already means I will take/have

The -m ending tells you it is I.

You can add já if you want emphasis or contrast:

• Já se vrátím z práce, ale on zůstane déle. = I’ll come back from work, but he’ll stay longer.

But in a normal neutral sentence, leaving out já is the most natural choice.

Because Až se vrátím z práce is a subordinate clause, and in Czech subordinate clauses are normally separated by commas.

So the structure is:

• Až se vrátím z práce, = subordinate time clause
• podívám se do zrcadla a dám si sprchu. = main clause

English also often uses a comma when a time clause comes first, so this part is fairly similar.

Some of it can change, but not completely freely.

The sentence as given is very natural:

• Až se vrátím z práce, podívám se do zrcadla a dám si sprchu.

You could also say:

• Až se vrátím z práce, dám si sprchu a podívám se do zrcadla.

That just changes the order of the two actions.

You can also move things around for emphasis, but you must still respect things like clitic placement:

• Až se vrátím z práce, do zrcadla se podívám až potom.
• Z práce se vrátím později.

So yes, Czech word order is flexible, but it is not random. Meaning, emphasis, and clitic rules all matter.