I started working consulting Aug 2022 but when trying to file my taxes it says that my business miles should be blank since the vehicle was in service after June 30?

In 2022 there was a change in the standard mileage rate so you must indicate the miles driven before June 30 and after June 30.  If you continue in the interview, you should see where you can enter the mileage for after June 30.

there is only a space for one. No way to enter the before mileage and the after mileage.  If you enter one here, where do you enter the other?

There is no place to enter both the before and after miles.   Only one space is provided.  Aren't you supposed to enter two numbers?

When going through the Vehicle Expense interview, after entering the type of vehicle, Date Placed in Service, and a few other questions, you should get a screen like this:

@JohnP10