How to make a cube fly upwards and to the left?

Would I do something like
rigidbody.AddForce(Vector3.Scale(Vector3.up500,Vector3.forward500),ForceMode.Acceleration);
?

You don’t Scale (multiply) the vectors, you add the vectors.

rigidbody.AddForce(Vector3.up*500+Vector3.forward*500,ForceMode.Acceleration);