Едва я открыл дверь, как собака начала лаять.

It is a common Russian pattern that shows one event happened and almost immediately another followed.

A very natural English equivalent is:

• Hardly/Scarcely had I opened the door when the dog started barking
• No sooner had I opened the door than the dog started barking

So едва here does not just mean barely in the usual sense; in this structure it has a temporal meaning: as soon as / hardly had ... when ...

No. In this sentence, как is not asking how something happened.

Here it is part of the fixed pattern едва ..., как ... and works like a conjunction, roughly equivalent to:

• when
• and then
• in the English pattern hardly ... when / no sooner ... than

So in this sentence, как is grammatical glue, not a question word.

Because Russian past tense agrees with the subject in gender and number.

With я, the form depends on whether the speaker is male or female:

• я открыл = a male speaker
• я открыла = a female speaker

So this sentence is said by a male speaker. If a woman were speaking, it would be:

• Едва я открыла дверь, как собака начала лаять.

Because the sentence refers to a single completed action that triggers the next event.

• открыть → perfective: to open as a completed event
• открывать → imperfective: to be opening / to open repeatedly / to open in general

In this sentence, the idea is:

• I opened the door
• then the dog started barking immediately

That calls for perfective: открыл.

If you used открывал, it would sound wrong here or suggest a different meaning, such as a repeated or ongoing action.

Russian can omit subject pronouns, but not as freely here.

The key reason is that the past-tense verb открыл does not show person. By itself, открыл could mean:

• I opened (if the speaker is male)
• he opened

So я is useful because it clearly identifies the subject.

In present tense, the verb ending often makes the subject obvious, but in past tense Russian often keeps the pronoun when needed for clarity.

Because дверь is the direct object of открыть, so it is in the accusative case.

The helpful thing here is that for this noun, the accusative singular looks the same as the nominative singular:

• nominative: дверь
• accusative: дверь

So the form does not change visibly, even though the case function does.

начала лаять means started barking, with a clear focus on the beginning of the action.

Compare:

• начала лаять = started to bark
• залаяла = began barking / barked suddenly
• лаяла = was barking / used to bark

So:

• лаяла would not fit as well, because it describes the barking as an ongoing or habitual action, not its sudden start.
• залаяла is actually possible and natural, but it is a bit more compact.
• начала лаять explicitly highlights the start of the barking.

Also, after начать, Russian normally uses an imperfective infinitive, which is why we get лаять, not a perfective infinitive.

Собака is a grammatically feminine noun, so the past-tense verb must also be feminine:

• собака начала

This does not always mean the actual dog is female. In everyday Russian, собака can be used for a dog in general, regardless of sex, unless the speaker wants to be specific.

If someone wants to emphasize that it is a male dog, they might use пёс, which is masculine.

Yes. The comma is required because the sentence contains two clauses:

• Едва я открыл дверь
• как собака начала лаять

Russian normally separates these clauses with a comma, and the pattern едва ..., как ... is written this way.

In this classic pattern, yes: едва ..., как ... is the standard pairing.

You may also see or hear other ways to express the same idea, for example:

• Как только я открыл дверь, собака начала лаять.
• Едва я открыл дверь, собака начала лаять.

But if you choose the full correlative construction used in your sentence, как is the expected word after the comma.

Yes, Russian word order is flexible, but the original order is very natural and neutral.

• Едва я открыл дверь, как собака начала лаять.

This order clearly sets up:

1. the first event
2. the immediate reaction

Other orders are possible, but they sound more marked or stylistically different. For example:

• Собака начала лаять, едва я открыл дверь.

That is still understandable, but it shifts the focus toward the dog’s action first.

So for a learner, the original word order is the best one to remember.