New phone and watsapp - help out an idiot please?

[OhComeOn123]

New phone (actually my Mum's old one). I take out the SIM in my old phone, put it in the new handset. Give it a few minutes to sort everything. A few apps automatically appear but not watsapp. So I download watsapp, it asks me to enter my phone number. I enter it. Then it sends a verification number to my old phone (which I've already switched off). But how will I be able to access this code if that handset has no bloody SIM in it?

I'll never make an IT technician me...

If you are at home, on Wi-Fi, then you don’t need the sim in the old phone. Just turn it on and the code should have been received 😊

It sends the text verification to the phone number - which should be working with the new SIM.

There is only one SIM. My current one, which I've transferred to the new phone.

Yep, so the text verification code appears on the new phone, with the SIM.

Yes. I was just about to post but PP beat me to it. The verification code goes on the sim so if you've entered the number of the sim your using, the verification code should come up on your new phone

Ps. You had to download WhatsApp because apps stay on the phone not sim. Your mum must have not had WhatsApp on the phone which is why you had to download it