In Spanish we use this verbal structure (known in grammar jargon La perífrasis verbal) to express "To begin/start doing[something]".
Empezar/comenzar (conjugated) a + Infinitivo
Have a look and listen to the following examples in different tenses:
Notice how the preposition "a" always follows empezar/comenzar. In Spanish, unlike in English, after "a" we do not use a gerund (-ing form) but the infinitive.
Marcos empieza a trabajar hoy.
Marcos empieza a trabajando hoy.
Marcos begins/starts to work today.
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