Whenever you start a campaign, or you load a saved one you will be able to enter and test your proxies.
Make sure you check your proxies in Kontent Machine before using them. Most tools, like Scrapebox, do not check if the proxies are suitable for scraping large amounts of content and they may appear working there but fail in KontentMachine.
The correct format for proxies is either “ip:port” or “ip:port:username:password” (for password-protected proxies)
If you are building multiple campaigns on a daily basis, it is recommended that you use either a VPN service or stable proxies. Otherwise the search engines and some article directories could quickly ban your IP, and you will not be able to download new content for some time. If you are using public proxies, make sure you update your list regularly because they can get banned pretty quickly.
However, if you are doing a couple of campaigns a day you can safely go without proxies at all.
My recommendation when it comes to proxies is BuyProxies.org