Learn Spanish (Latin America): Me levanto a las siete de la mañana.

The verb here is levantarse (to get up), which is a reflexive verb. In Spanish, when you do an action to yourself, you use a reflexive pronoun like me. Me levanto literally means "I raise myself" or "I get myself up".

Do I need to say yo me levanto?

You can, but it is not required. Because the verb form levanto already tells us that "I" am doing the action, the word yo (I) is understood. Spanish speakers usually drop the yo unless they want to add special emphasis, like "Well, I get up at seven."

Why do we use las before siete?

In Spanish, telling time is tied to the word hora (hour), which is feminine. Even though the word horas is left out here, we use the feminine plural article las to match it. You will use las for all hours except one o'clock, which uses the singular la (la una).

Why does it say de la mañana instead of en la mañana for "in the morning"?