Open house listings have three main components, listing office, host agent, and the listing itself.

Start by choosing an office type, Agency or By Owner. If Agency, select the agency from the pull-down menu. If the office is not listed, click the 'Add an office' link. If By Owner, click the 'By Owner' button and enter a phone number for the listing.
When an office is selected, a menu of agents attached to that office appears. Select the listing agent. If the agent is not listed, click the 'Add an agent' link.

Finally, the listing. Select a publication date for the ad. The first Friday after the current date will already be filled in. Enter the address as it appears in the ad. Enter the city. Enter the date and time of the open house as it appears in the ad. Same for directions (do not type 'Directions:', that's added automatically). The 'Header:' field is for a bold, larger line of type above the description. The 'Description Heading:' is bold type that appears at the beginning of the description. The 'Description:' is just that, the body of the ad. If your description is a two-column list and not a paragraph format, click the 'two-column' radio button and enter your list items. Don't start them with bullets or anything else, the bullets are added automatically on the output side. The 'Footer:' field is for a bold, larger line of type below the description, commonly used for a price.