Za hodinu začne porada.

Here za means in in the sense of after a certain amount of time from now.

So:

• Za hodinu = in an hour
• Za pět minut = in five minutes
• Za týden = in a week

This is different from other meanings of za, which can also mean things like behind or for in other contexts.

Because after za with this time meaning, Czech uses the accusative case.

The base form is:

• hodina = hour

But in the accusative singular it becomes:

• hodinu

So:

• za hodinu = in an hour

Because za hodinu and v hodinu mean different things.

• za hodinu = in an hour / after one hour from now
• v hodinu = at one o’clock (or literally at an hour, though in practice you usually say v jednu hodinu)

So:

• Za hodinu začne porada. = The meeting starts in an hour.
• Porada začne v jednu hodinu. = The meeting starts at one o’clock.

Because začne comes from the perfective verb začít (to begin / to start). In Czech, present-tense forms of perfective verbs usually refer to the future.

So:

• začne = will begin / will start

This is very common in Czech. A perfective verb often does not have a true present meaning in normal use.

The dictionary form is začít.

In this sentence, začne is:

• 3rd person singular
• from začít
• meaning will begin

So začne porada literally means the meeting will begin.

Because Czech does not always need a separate word like will.

Here the future is shown by the verb itself:

• začne already means will begin

That is because začít is a perfective verb, and its present forms naturally express future meaning.

Porada is in the nominative case because it is the subject of the sentence — it is the thing that will begin.

So in:

• Za hodinu začne porada.

the subject is porada = the meeting

Yes. Czech word order is flexible.

You can also say:

• Porada začne za hodinu.

Both versions are correct. The difference is mainly in emphasis:

• Za hodinu začne porada. emphasizes when
• Porada začne za hodinu. starts with the meeting as the topic

In many contexts, both sound natural.

Yes, you can, but za hodinu is usually more natural.

• za hodinu = the normal way to say in an hour
• za jednu hodinu = possible, but more explicit or emphatic

English often uses an hour, and Czech usually just uses the noun without jednu here.

Czech has no articles, so porada can mean either the meeting or a meeting, depending on context.

So the sentence could be understood as:

• The meeting will start in an hour
• or A meeting will start in an hour

Usually the surrounding context makes it clear.

You negate začne by adding ne-:

• Za hodinu porada nezačne.
• Porada za hodinu nezačne.

This means:

• The meeting will not start in an hour

Again, the word order can vary depending on emphasis.

This is a very useful distinction:

• za hodinu = in an hour / one hour from now
• během hodiny = within an hour or during the hour

So:

• Za hodinu začne porada. = The meeting starts one hour from now.
• Porada začne během hodiny. = The meeting will start sometime within the next hour.

These are not the same.