За час до вебинара я проверю микрофон и камеру.

This is a very common Russian time pattern:

за + amount of time + до + event

So:

• за час = by an hour / one hour before
• до вебинара = before the webinar

Together, за час до вебинара means an hour before the webinar.

Russian often uses both parts in this expression. It is the normal way to say that something happens a certain amount of time before another event.

Examples:

• за день до поездки = a day before the trip
• за пять минут до урока = five minutes before class

Because до requires the genitive case.

The base form is вебинар. After до, it changes to вебинара.

So:

• вебинар = webinar
• до вебинара = before the webinar

This is a rule you will see very often:

• до урока = before the lesson
• до встречи = before the meeting
• до работы = before work

Here час is in the accusative singular, because of the preposition за in this time expression.

The pattern is:

• за час до... = an hour before...
• за день до... = a day before...

With masculine inanimate nouns like час, the accusative singular looks the same as the nominative singular, so you see час.

Compare:

• nominative: час
• accusative: час

But with other words, the form may be more obviously different.

Проверю is the 1st person singular future form of the verb проверить.

It means I will check.

This verb is perfective, so its future form is a simple future:

• я проверю = I will check

Perfective verbs usually focus on a single completed action or the result of an action. In this sentence, the speaker means they will do the check as a complete preparatory step before the webinar.

This is a very important aspect difference in Russian.

• проверю = I will check / I’ll make sure everything is checked

  • perfective
  • one complete action
  • focus on result

• буду проверять = I will be checking / I will check

  • imperfective
  • focus on process, duration, or repeated action

In this sentence, проверю sounds natural because checking the microphone and camera is a specific, completed task.

Compare:

• За час до вебинара я проверю микрофон и камеру.
  = I’ll check the microphone and camera an hour before the webinar.

• Перед каждым вебинаром я буду проверять микрофон и камеру.
  = Before every webinar, I will check the microphone and camera.
  Here the repeated/habitual sense makes imperfective more natural.

Both nouns are direct objects of проверю, so they are in the accusative case.

Their dictionary forms are:

• микрофон
• камера

Now look at the accusative:

• masculine inanimate nouns often stay the same:
  • микрофон → микрофон
• feminine nouns ending in -а usually change to -у:
  • камера → камеру

So:

• проверю микрофон
• проверю камеру

This is why one looks unchanged and the other changes form.

Yes. Russian often drops subject pronouns when the verb ending already makes the subject clear.

So both are possible:

• За час до вебинара я проверю микрофон и камеру.
• За час до вебинара проверю микрофон и камеру.

Both mean the same thing.

Including я can add a little clarity, contrast, or emphasis. Without я, the sentence may sound slightly more neutral or conversational.

No, Russian word order is fairly flexible.

The original sentence:

За час до вебинара я проверю микрофон и камеру.

This is natural because it puts the time frame first: an hour before the webinar.

You could also say:

• Я проверю микрофон и камеру за час до вебинара.

That is also correct. It may sound a bit more neutral if you want to focus first on what I will do, and then add when.

Russian word order often depends on what the speaker wants to emphasize rather than on a rigid grammatical rule.

Usually it means an hour before, but in real speech it can sometimes be understood a little loosely as about an hour before, depending on context.

If someone wants to be very exact, Russian can make that clearer through context or by adding words. But by itself, за час до вебинара normally gives the straightforward idea of one hour before the webinar.

Russian does not have articles like a, an, or the.

So вебинар, микрофон, and камера can mean:

• a webinar / the webinar
• a microphone / the microphone
• a camera / the camera

The exact meaning is understood from context.

In this sentence, English naturally uses the webinar, the microphone, and the camera, but Russian does not need separate article words.

A natural stress pattern is:

За час до вебинАра я провЕрю микрофОн и кАмеру.

Key word stress:

• вебинАра
• провЕрю
• микрофОн
• кАмеру

A rough pronunciation guide:

• Za chas do vebinAra ya provEryu mikrofOn i kAmeru

For English speakers, one useful point is that Russian stress is mobile and must often be learned word by word.