Signed 2019 BMW X3 Loaner - Help with calculator

I have signed below deal on a BMW X3 Loaner , I tried putting the numbers onto calculator but not able to figure it out on how to arrive at the monthly payment of ($343)

Demo Mileage :4614
Due at signing:$2260
Tax : 6.35
Monthly : $343 With Tax

Add the link to your calculator…also what’s the MF?

That is a great deal sign now.

Is this so cal?

where did you buy this car?