Я їм сніданок перед тим як я йду на роботу.

їм is the imperfective present-tense form of їсти (“to eat”) for “I.”
• Imperfective verbs describe ongoing or habitual actions (here “I eat breakfast”).
• The perfective form з’їсти has no true present tense—its so-called “present” я з’їм actually means “I will eat” (future).
• If you wanted to say “I have eaten breakfast” (completed action), you’d use the past perfective: Я з’їв сніданок.

перед тим як is a subordinating conjunction meaning “before (the time) that…,” used to link two clauses.
• перед + noun (e.g. перед роботою) only forms a noun phrase (“in front of” or “before [something in time]”).
• To introduce a clause with its own verb (я йду), Ukrainian needs “before that as”: перед тим як.
• You could also say до того як or перш ніж, which serve the same function (see a later question).

Yes. In Ukrainian, subordinate clauses are set off by commas. The standard punctuation is:
Я їм сніданок, перед тим, як я йду на роботу.
• Comma before перед тим marks the start of the subordinate clause.
• Comma after тим is part of the fixed conjunction перед тим, як.
Many writers simplify to one comma:
Я їм сніданок, перед тим як я йду на роботу.

In Ukrainian, the imperfective present can express habitual actions or general truths—just like in English “I eat breakfast before I go to work.”
• Here it’s a routine: you habitually go to work after breakfast, so both verbs are present.
• If you wanted to speak of a single future trip, you’d choose the perfective future: я піду на роботу (“I will go to work”).

на + accusative expresses direction (“to/toward”).
• робота is feminine; its accusative singular is роботу.
• йти на роботу is the everyday idiom for “to go to work.”
• до роботи (genitive) would literally mean “toward the location of work,” but it’s not the standard collocation here.

Yes. In Ukrainian subject pronouns are usually optional because verb endings show person and number.
• йду already means “I go,” so you can simply say перед тим як йду на роботу.
• You might keep я for emphasis or clarity, especially in longer sentences.

Yes. Other common conjunctions for “before” + clause:
• перш ніж (e.g. перш ніж я йду на роботу) – shorter, fairly colloquial/formal.
• до того як (e.g. до того як іти на роботу) – more literary, often used with an infinitive: до того як іти.
All three are interchangeable in meaning; choice depends on style and register.

Absolutely. Ukrainian allows fronting the subordinate clause:
Перед тим як я йду на роботу, я їм сніданок.
or more concisely
Перед тим як йду на роботу, я їм сніданок.
Remember to place a comma after the introductory time clause.