Header bidding is a technology which allows to run a realtime auction on publisher's side. This decrease page latency and increase the CPM rates.
When page is loaded the script in the header sends out bid requests to ad partners simultaneously, gets bids for ad spot and shows ads at the highest rate. If no bids return standard waterfall setup is initiated.
So, you can run both header bidding and traditional waterfall ad serving setup on the same page.

You will need to create and tune HeadBidder.net wrapper. It is a core script that sends out requests and collects the bids. And add it to the header of your website.
Now you are able to manage all bidders you added from one GUI.

HeadBidder.net designed to be simple, safe and effective in use for web developers.
All you need is the basic web development experience which you already have since you have been running the website. Also you are always can send your questions to support team at support@headbidded.net.

HeadBidder is a request-per-ad-spot-based service. That means that it counts 1 request from one ad spot.
Then, on the platform it allows an unlimited number of bid requests to an unlimited number of adapters.

Joint use of Google Ad Manager and HeadBidder.net increases average revenue uplift greatly as you allow additional competition between HeadBidder's winner and Google's winner. HeadBidder's unsold still can be monetized through your Google Ad Manager setup.