Check this module on Varsity to know more about an IPO. The process to apply for any IPO in SBI has been explained here.
For evey IPO you can submit 3 bids in the defined price band, in this case, Rs.145 - 149. If you are expecting the issue to be oversubscribed you can place a single bid at the higher price band because that will become the cut off price post the issue close. But if you think the issue won’t be oversubscribed you can place multiple bids at the lower price bands. The difference between the application and cutoff price will be refunded back to you,