Once you have shared a campaign with a source, that source will then be able to access the posting docs for that campaign, which contain the information needed for sending a post through.
The posting docs can be accessed from a campaign by clicking on the 'lead post docs' in the top navigation.
This document should outline all of the information needed to pass a lead - including system parameters, like your account id and campaign id as well as all of the campaign parameters. It also includes server response information and sample form code.
It is best for each source to get the posting docs from within their own LeadConduit account.
If you are providing posting docs to a source or site who cannot or does not want to login to LeadConduit, you can access source-specific docs to provide to them by clicking to the campaign in your account, selecting the lead post docs link as above, then selecting the specific account or site in the dropdown menu.