In a simple statement, the conjugated verb has a fixed position. It is always in second position. The position of the subject is freer. It often comes at the beginning of the sentence, before the conjugated verb.
However, other parts of the sentence can also come at the beginning if we want to give them emphasis. These are often details about time or place. Then the subject comes after the conjugated verb, i.e. in third position.
Example: Time detail: jetzt
Example: Place detail: in Frankreich*
*In this case, the place detail consists of two words. Since these two words belong together, they occupy first position together. The verb comes in second position here too.
Sometimes other sentence parts also come in first position.