⇒ soy = I am/I'm when talking about permanent or lasting attributes

⇒ estoy = I am/I'm when talking about temporary states or locations

⇒ estoy is also used as an auxiliary verb in the present continuous.

Soy alta, soy mexicana y soy ingeniera. I'm tall, I'm Mexican, and I'm an engineer.

Estoy cansado y hambriento. I'm tired and hungry.

Estoy en el banco. I'm at the bank.

Estoy corriendo en el parque. I'm running in the park.

⇒ Learn more about the differences between ser and estar here!