1
I need to go to the store.
Sign "I", "need", then use the "go to" sign moving outward from your body, followed by the sign for "store". The direction of your "go to" sign can point generally forward, or you can point it toward the specific area where you previously established the store in your signing space.
2
Are you going to the party?
Point directly to the person for "you", sign "go to" moving forward, and then sign "party". Because this is a yes/no question, remember to keep your eyebrows raised and lean forward slightly while signing the entire sentence to show you are asking for a response.
3
We went to the park yesterday.
Start by signing "yesterday" to establish the timeline, point to yourself and others for "we", use the "go to" sign, and finish with "park". ASL doesn't change the verb for past tense; the time word "yesterday" already makes it clear that the action has happened.