Help plz ? Best way to use proxy for hundreds of Facebook accounts ? How to buy accounts ?

Hi friends, thank you in advance for your help.

I will be using a program to control hundreds of Facebook accounts and it says I need dedicated proxy to do that.

Could you please explain what kind of proxy should I get and what is the best way to use these proxies ? E.g each profile must have it's own address ? Or many profiles can share one address ? If so how many profiles can I use safely on 1 address ?

Where to get the best proxies and how do you just if proxies are quality or not for Facebook profiles ?

Also should I need sequential IP or non sequential IP ? I don't have a clue what these mean actually, I just saw these on the offers

What important things should I know which could break things up when buying accounts and IPS ? For example I saw that I have to buy American FB profiles and these profiles have to match with American IPs ? Is it true ?

If there is anything I should and I have missed could you please let me know ?

Thank you soooo much for your help