Every month, each server owner can put his server at the top of the first page for a whole month. To win the "Premium" option, you have to be in the top X bidders, where X is equal to the number of slots available.
The top bidders will be displayed at the top on the first page of the site.
The top bidders will be displayed also at the top of search results, their country pages, tag pages and version pages (if they fits the criteria).
Each server owner who want the "Premium" option has to participate in the bid system. The top X bidders will win the "Premium" option for their servers. At the end of the bidding process, the top X bidders will have 3 days to pay their bids. X is equal to the number of slots available.
The fact for anyone to buy a service on the website "Rust-Servers.net" implies full acceptance of these terms and conditions which the buyer acknowledges prior to its purchase.
You can read them here : General Terms And Conditions of Sale
Maybe. You only need to pay if you are in the top bidders, but you may be placed in the top if one or more bids do not get paid and your bids take their spot, making you obligated to pay. Do not place a bid until you are absolutely positively sure you agree to pay the amount you have placed.
At the end of the bidding process, a Paypal button will appear for the top bidders. If you are in the top bidders, you will have until payment limit date to pay.
The bid that was placed the earliest will take precedence and will have the highest position with that value.