What is market price on grant date for ESPP stock sale

My 1099-B shows unknown for the sale of some stock purchased over years through the ESPP offered.
I also received no 3922 form. I am trying to calculate cost basis using the Investment reports from my broker which shows the purchases. To enter this in Turbo Tax, I am not sure how to find the market price on grant date.

What should be entered for Market price on grant date ? Is the grant date considered the start of the offering period, or the settlement date when the stock was received ( 7/10/2024 )? In addition, what closing price do I use if the beginning of the offering period is a weekend (6/03/2024) ?