Get guest phone number

[MVS__]

Hey guys,

I want to modify the PrestaShop checkout in the following way:

In the checkout - first step I want to request guest mobile phone and store it in abandoned cart. therefore, if the guest will not finish his order by different reasons, I will have his phone and ask what is the problem.

What I know until now:: When somebody is in the store, PS creates the abandoned cart. When you select different carriers, PS record info in DB, without customer info to be completed. When you press submit order, data is stored in abandoned cart, until you press confirm order. So the methods for saving the context are there, they just need to be put in the right order. Can somebody please help me what do I need to do in order when a guest leave the Mobile Phone box (which will be moved in the first row) after the phone validation, to automatically store the phone in the DB (and also the consequence of this - when he/she finish the order to update the phone filed or just to not have aberations in the phone field like phone for 2 times or to record a new address)

Thank you and I am waiting for some sugestions

[MVS__]

Anyone pls?