Just bought Huawei G300 - Help

[Guest kido44]

Hi all, I'm new on here and read quite a few threads but wondered if someone would help me set up my new G300.

I've bought it on vodaphone so need it unlocked to enable 3uk.

Do I have to unlock the phone first (using eBay to get a code) or if I flash a custom rom will this unlock the phone?

That aside, to get jelly bean on my g300 do I need to root the phone first and then just flash a custom jelly bean rom and go from the basic stock software streaming to the custom jelly bean rom? Or do I need to update the rom first?

Sorry if I'm asking simple questions but I'd appreciate any help.

Thank you