Learn Finnish: Kokoaikainen yrittäjä työskentelee paljon.

It comes from the verb yrittää, which means "to try" or "to attempt." The suffix -jä is added to the verb stem to describe the person doing the action. Literally, an entrepreneur in Finnish is a "tryer."

Why use työskentelee here instead of tekee töitä?

Both are perfectly correct and mean "works," but työskennellä (the infinitive form of työskentelee) is a single verb that often sounds a bit more formal or professional. Tehdä töitä (to do jobs or work) is very common in spoken language, but you can usually use them interchangeably at this level.

How is the adjective kokoaikainen (full-time) built?

It combines koko (whole) and aika (time) with the adjective-forming suffix -inen. When you want to use a noun combination like kokoaika to describe another word (like yrittäjä), attaching -inen turns it into a proper adjective.

How would you use this lesson's "tulla" transformation to say "I become a full-time entrepreneur"?

You would put the pronoun in the Elative case (minusta), use the third-person singular verb tulee, and leave the new role in the Nominative case: Minusta tulee kokoaikainen yrittäjä. This literally translates as "Out of me comes a full-time entrepreneur."