Во время вебинара мне хочется задавать вопросы, если что‑то непонятно.

Во время is a fixed prepositional phrase meaning during and it requires the genitive case:

• во время (чего?) вебинара
  You can’t say в время in this meaning. В
  • time words is used differently (e.g., в то время = at that time / while).

Вебинар is a masculine noun, so the genitive singular is вебинара:

• nominative: вебинар
• genitive: вебинара
  It follows the common pattern for many masculine nouns: -Ø → -а in the genitive singular.

Мне хочется is an impersonal construction meaning something like I feel like / I have the urge. It’s less direct and more about an inner desire.

• я хочу = a straightforward, deliberate I want
• мне хочется = I feel like, often softer/more spontaneous

Grammatically, мне is dative because the “desire” is presented as happening to you:

• мне (кому?) хочется = to me it feels like (doing something)

After (мне) хочется, Russian typically uses the infinitive to express what you feel like doing:

• мне хочется + infinitive
  So мне хочется задавать = I feel like asking (to ask repeatedly / in general).

You can also use a noun sometimes, but the infinitive is the most common pattern.

In Russian, the natural collocation is задавать вопросы (to pose/ask questions).
Спрашивать is used differently:

• спрашивать (что?) can mean to ask (a question), but more often you ask someone something:
  • спрашивать преподавателя (to ask the teacher)
  • спрашивать о чём‑то (to ask about something)
  • спрашивать, где... (to ask where...)

So задавать вопросы is the standard “asking questions (as a set/regularly)” phrasing.

Задавать (imperfective) suggests a general, repeated, or ongoing action: asking questions during the webinar whenever needed.

Задать (perfective) would point to a single, completed act (or a limited set as a whole), for example:

• мне хочется задать вопрос = I feel like asking a question (one specific question)

Your sentence uses задавать вопросы because it’s about the general behavior during the webinar.

Because если что‑то непонятно is a subordinate conditional clause (if something is unclear). In Russian, such clauses are normally separated by a comma:

• ..., если ...

It’s a common Russian pattern where the “verb to be” is omitted in the present tense.

• что‑то = something (pronoun)
• непонятно = short-form predicative meaning unclear / not understandable

So it’s equivalent to:

• если что‑то (есть) непонятно = if something is unclear

что‑то is a pronoun formed with the particle -то, which is written with a hyphen. It usually means something / somehow / some kind of, often implying “some unspecified thing”:

• что‑то непонятно = something is unclear
• кто‑то = someone
• где‑то = somewhere

It’s different from что-то? as two words (which would be unusual here); the hyphenated form is the standard pronoun.