What will happen when shares are bought using cash option instead of cash upfront option using vickers?

Will the shares be in CDP or under custodian? Also, if i were to sell do i have to tick the contra box? Or sell normally like the usual way as I already have some of the same shares bought using cash upfront and is already in my CDP.

My MCA account is also not deduct after the order being filled. How do I actually “pay” for the shares then?