אם אין לך זמן, אני אלך לבד.

Here אם means if.

It introduces a condition:

• אם אין לך זמן = if you don't have time

Hebrew אם can also mean whether in other contexts, but in this sentence it clearly means if.

Because Hebrew usually expresses having with יש/אין, not with a separate verb meaning to have.

So:

• יש לי זמן = literally there is time for me = I have time
• אין לי זמן = literally there isn't time for me = I don't have time

So אין לך זמן is the normal Hebrew way to say you don't have time.

אין is used to negate existence or possession.
It is the negative partner of יש.

• יש זמן = there is time
• אין זמן = there is no time

לא is the regular negation for verbs and many other sentence types:

• אני לא הולך = I am not going
• הוא לא יודע = he doesn't know

Since this sentence is using the Hebrew possession pattern יש/אין, you need אין, not לא.

לך means to you.

In Hebrew, possession is often shown with ל־ (to/for) plus a pronoun:

• לי = to me
• לך = to you
• לו = to him
• לה = to her

So:

• אין לך זמן literally means there is no time for you
• natural English meaning: you don't have time

In normal unpointed Hebrew writing, לך can be either:

• לְךָ = to you when speaking to a man; pronounced roughly lekha
• לָךְ = to you when speaking to a woman; pronounced roughly lakh

Both are written לך without vowel marks, so the sentence could be addressed to either a man or a woman. You tell from context or from speech.

אלך is the first person singular future form of ללכת (to go).

So:

• אלך = I will go

This verb is somewhat irregular, so it does not look exactly like the dictionary form ללכת.

A useful mini-pattern:

• אני אלך = I will go
• אתה תלך = you will go
• הוא ילך = he will go

Yes — Hebrew could simply say אלך לבד.

Since the verb form already shows I, the pronoun אני is not strictly necessary.

So:

• אלך לבד = I'll go alone
• אני אלך לבד = also I'll go alone

Including אני can add clarity, emphasis, or just sound natural in conversation. Modern Hebrew often uses subject pronouns even when they are optional.

לבד means alone or by myself.

So:

• אני אלך לבד = I will go alone / by myself

It comes at the end because that is a very natural place for it in Hebrew. It describes how the speaker will go.

Yes. For example:

• אם לא יהיה לך זמן, אני אלך לבד.

That means something like If you won't have time / if you don't have time, I'll go alone.

But אם אין לך זמן is also very natural, especially when talking about a real or immediate situation. Hebrew often uses the present form in the if clause where English might also talk about the future.

The comma separates the condition from the main result:

• אם אין לך זמן = the condition
• אני אלך לבד = the result

So the structure is:

• If X, Y

The comma is standard and helps readability. In speech, there is usually a small pause there too.