Learn Hardcore Portuguese (Portugal): O engenheiro estuda o regulamento antes de começar o projeto. - The engineer studies the regulation before starting the project.

In European Portuguese we normally use definite articles before nouns acting as subjects (except after the verb ser). When you say a profession with any verb other than ser, you keep the article.
Examples:
• O médico trabalha muito.
• A professora explicou a lição.
If you used ser, you’d omit it: Ele é engenheiro.

Why is the simple present estuda used instead of a continuous form like “is studying”?

Portuguese often uses the simple present to express both habitual actions and ongoing events. So estuda can mean “he studies” or “he is studying.” To stress the continuous aspect in European Portuguese, you can use:
• O engenheiro está a estudar o regulamento.
Using estar + a + infinitive is the typical EP continuous form.

How does the structure antes de começar o projeto work? Why do we say antes de + infinitive?

When the same subject performs both actions, Portuguese uses antes de + infinitive:
• Antes de começar o projeto (Before starting the project)
Here de is mandatory. You cannot say antes começar.
If the subjects differ, you switch to antes que + subjunctive:
• Ele estuda o regulamento antes que o colega comece o projeto.