how do i change my phone

[old-git]

i have inherited a samsung Galaxy phone and want to use it as a payasyougo phone. I have a new sim and put it in. what do i do next as it doesnt communicate. i already have a payg phone which is rubbish and want to transfer the number to this new phone.

old git

[Cleoriff]

@old-git 

You have to top up to activate the sim

Guide How to Top Up (PAYG) 

If you want to keep your number, you need to do a sim swap Guide: Sim Swap: a mini guide 2017 update 

[MI5]

@old-git 

If your old sim fits, just use that and everything will carry on as normal.