Before an advertiser is able to use the link between DV and the site, Hexon needs to be granted permission by both the advertiser, or the reseller on its behalf, and the site.
Though Hexon always need explicit permission from the advertiser or its reseller, sites can instruct Hexon not to ask for their permission, but instead allowing all new advertisers by default. Sites can still revoke permission if needed.
Usually the advertiser or its reseller will inform Hexon of the intention to use the link (and thereby granting Hexon permission). Hexon then contacts the site to request permission.
The communication with the site regarding the permission is usually done via email, but can also be automated using the API of the site.
It is also possible for the site to initiate the request by creating a link request using the API or DV Insite. Having been granted permission from the site, Hexon contacts the advertiser (or its reseller) to request permission.
As described in III.3.1. Account identifier, in most cases the account identifier also needs to be exchanged. This is usually done together with requesting the permission. DV can also automatically register new accounts if the API of the site allows for this. DV also supports mechanisms like OAuth to gain access to accounts.