Learn Hardcore Arabic (Modern Standard): سوف أبدأ هذا الدرس قبل الغداء.

سوف is a future marker. It tells you the action will happen in the future: I will start…
It’s placed before an imperfect (present-form) verb: سوف + أبدأ.

Is أبدأ a present tense verb or a future tense verb?

Formally, أبدأ is the imperfect (often taught as “present tense”) form meaning I start / I am starting.
Adding سوف turns the meaning into the future: سوف أبدأ = I will start.

What’s the difference between سوف أبدأ and سأبدأ?

Both mean I will start.

سأبدأ (with the prefix سـ) is very common and slightly more direct/neutral.
سوف أبدأ can feel a bit more deliberate or slightly more “formal,” and sometimes suggests a less immediate future, though in practice they often overlap.

Why is the verb written أبدأ with a hamza (أ)?

Because the verb is from the root ب د أ (to begin). In the 1st person singular imperfect, Arabic adds أ- (I…) to the verb:

أبدأ = I begin / I start
The hamza here is part of the standard spelling of this form.