How Advertising Works
From Legacy Roblox Wiki
Creating an add
To create an add, go to one of your place's pages' and press the link "Advertize this place" underneath your avatar.
This will bring you to a page where you can get the add templates, and upload adds.
Using an add
Once you have created and uploaded and add, you can now display it. Go to you profile and press "add inventory". This brings you to a page where you can run you adds on the site. To start running an add, press "Run add" on the right side of the pane. You have to bid money to get you add put up over other people's adds.
Add statistics
Impressions: How many times you add has been shown on a page so far.
Clicks: How many time people have clicked you add.
CTR: What percentage of showings resulted in people clicking on the add.
Bid: How much you bid