Question

Nosotros debemos ir a la tienda.
How do you turn this into a singular persons point?

Answer 1

(yo) debo ir a la tienda .
I need to go to the store

Answer 2

answer : yo tengo que ir a la tienda

Answer 3

Just check your verb tense table... yo debo, tu debes, él debe, nosotros debemos. This is a composed phrase as the "debo" refers to an action, which is "ir a la tienda" (going to the store)... if it is easier for you, maybe see the phrase as building blocks that you can change according to the "person" speaking or participating of the action. hope this helps!