Lightroom : Moving LR 6.12 from a PC to another one

I used LR 6.12 on an old PC, want to cancel it and to reinstall it to a new one..

Which procedure to use ?

Where to find LR6 downloading ? Do I have to begin with LR6.0 and then upgrade or install directly 6.12 ?

How to proceed with activation codes ? and where ?

Is there a 6.13 version ?

In advance thank you and best regards.