You can only leave remarks such as "Just Listed" or "Coming Soon" for listings if they are your own ones. So this article doesn't concern the MLS® listings. 

If you have an open house date entered, that of course is the most important note concerning this listing. So other notes like "Just Listed" won't be shown as a banner any more. Instead the banner will look like this:

How to enter an Open House Date:

Entering such an "Open House" note for a listing is very easy. Just go to "Manage Listings".

Now "edit" the listing.

Under "Basic Info" you can enter the date for the upcoming Home Tour.