How can i claim a phone number at Amazon Connect.

The procedure is as described in this document.

1. Log in to Amazon Connect at https://instance name.my.connect.aws/.
2. On the navigation menu, choose Channels, Phone numbers.
3. Choose Claim a number. You can choose a toll-free number or a Direct Inward Dialing (DID) number.
4. Enter a description for the number and, if required, attach it to a contact flow in Flow / IVR.
5. Choose Save.
6. Repeat this process until you have claimed all your required phone numbers.

https://docs.aws.amazon.com/connect/latest/adminguide/get-connect-number.html