How does ASBA system work for IPO?

Bhai I saw this post today only. And I will answer to the questions. I understand it is late n probably you have found your answers.
1) Bhai. Let me give you an example regarding ASBA. Say I am a popular sweet shopkeeper. You want to buy sweets. And since I am popular, I will ask you to give me money in advance. If I can’t fulfill your order then I will return your cash. There are a lot of complexities in this system. What if I don’t honour the obligation. Etc etc.
2nd situation. We ll develop a financial solution, in which your money ll lie in your bank. If you place an order, say 100₹, 100₹ will be put in Lien. If I deliver your order, your money ll be put deducted. If I don’t fulfill my obligation within stipulated time frame, then lien money ll be unblocked and wil be credited back to your acc. And if you do not have 100₹ in your bank you can’t put a order request.
Same thing here. After applying for IPOs, the money required gets blocked. If you get the shares, then money deducts from the bank account. If you don’t then the money gets unblocked

I use Zerodha. And if we change our Demat Account, and wish to move shares to the new acc, we need to request our existing brokers for the same. Here is the process
https://support.zerodha.com/category/your-zerod...

Wrt upcoming SBI Cards IPO, please guide if we have SBI shares, can we apply in sharholders category and retail category both or only one application per PAN is allowed?