Once you've found a site you like, all you need to do is send the publisher your offer. For this you need to indicate which type of link you want, the html code to be integrated, and the price that you think this deal is worth. In the case of sponsored articles we also recommend that you provide additional instructions for the publisher.
Publishers then choose if they want to accept your offer, send you a counter offer, or refuse it. You can of course send them a different offer afterwards.