Vytvořím nový soubor.

Because vytvořit is a perfective verb. In Czech, the present-tense forms of perfective verbs usually refer to the future.

So:

• vytvořím = I will create
• not I create in the usual present-time sense

If you want to say I am creating or I create as an ongoing/habitual action, Czech normally uses the imperfective verb vytvářet instead.

For example:

• Vytvářím nový soubor. = I am creating a new file.
• Vytvořím nový soubor. = I will create a new file.

It comes from the verb vytvořit, which is a perfective verb meaning to create / to make / to produce.

Vytvořím is:

• 1st person singular
• perfective
• formally a present-tense form, but used with future meaning

So it means I will create.

Czech often leaves out subject pronouns when they are already clear from the verb ending.

The ending -ím in vytvořím already tells you the subject is I.

So:

• Vytvořím nový soubor. = I will create a new file.
• Já vytvořím nový soubor. also means the same thing, but já adds emphasis, contrast, or extra clarity.

For example, Já vytvořím nový soubor, ty upravíš starý. = I’ll create a new file, and you’ll edit the old one.

Because soubor is the direct object of the verb, so it goes in the accusative case.

Here, soubor is:

• masculine inanimate
• singular

For masculine inanimate nouns, the accusative singular is usually the same as the nominative singular. The adjective matches that pattern too.

So:

• nominative: nový soubor
• accusative: nový soubor

That is why the sentence uses nový soubor.

By contrast, with a masculine animate noun, the accusative would look different:

• Vidím nového učitele. = I see a new teacher.

It is in the accusative singular.

The verb vytvořit normally takes a direct object answering what?

• Vytvořím co? → nový soubor

So soubor is the thing being created, which makes it the direct object.

Yes. Czech word order is fairly flexible, because case endings and verb forms carry a lot of grammatical information.

The most neutral order here is:

• Vytvořím nový soubor.

But other orders are possible, depending on emphasis:

• Nový soubor vytvořím. = emphasizes the new file
• Soubor nový vytvořím. = possible, but much less natural in ordinary speech

In normal everyday usage, Vytvořím nový soubor is the most straightforward choice.

This is a very common and important question, because it involves aspect.

• Vytvořím nový soubor.
  Focuses on the action as a completed whole: I will create a new file.

• Budu vytvářet nový soubor.
  Uses the imperfective future and focuses more on the action as ongoing, in progress, or not viewed as completed: I will be creating a new file / I will create a new file in a process-oriented sense.

In many contexts, English uses the same future form for both, but Czech makes the distinction more clearly.

Often, yes. In modern Czech, soubor very commonly means file, especially in computer contexts.

Depending on context, soubor can also mean:

• a set
• a collection
• an ensemble/group

But in a sentence like Vytvořím nový soubor, the default interpretation is very likely a new file.

A rough pronunciation guide:

• vytvořím ≈ VIT-vo-rzheem
• nový ≈ NO-vee
• soubor ≈ SOH-bor (with ou sounding roughly like oh-oo blended together)

The hardest part for many learners is ř, a special Czech sound. It is somewhat like a combination of r and zh (as in measure), produced together.

You do not need a perfect ř immediately. Many learners first aim for something between:

• r
• zh
• or a soft rzh

That is a normal stage in learning Czech pronunciation.

It is capitalized simply because it is the first word of the sentence.

There is nothing special about the verb itself that requires capitalization. In the middle of a sentence, it would normally be lowercase:

• Zítra vytvořím nový soubor. = Tomorrow I will create a new file.