You can create a new Ad on Newsfeed by clicking on "Create new Ad" button at the top.
The popup will show up where you can select an Ad host (your profile), type an Ad title, select an Ad image, choose an Ad plan and type a short description of your Ad.
Other way you can create a new Ad is clicking on "Create a new Ad" button on My Ads page.
Creating a new Ad is not free.
Note: In order to create a new Ad you have to have at least one profile because all advertising goes through profiles. You can create your first profile for FREE.
Read What is the advertising plan, How to pay and use services at Partyaner, Price list, How to create a profile on Partyaner and Terms of Purchase for more information.