When I go to iMessages to send and receive, it says waiting for activation

I just bought my phone yesterday. When I go to iMessages to send and receive, it has my email address, under there it says, waiting for activation. I’m having trouble understanding how to have my phone receive and reply from my phone number not my email. It’s circulating around my phone number waiting for activation. What can I do?

also, my phone msg’s me with, I have a new memory.... I would like to know how do I shut this off?

thank you

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