You can find it right under the title of your ad in My Account. When you have clicked on it, it becomes grey and you should wait for 20 minutes to have it again.
All you have to do is click on the blue link Multi-repost every time it is available. This button becomes available once you purchase the option.
Your ad can go on the top listing whenever you wish with a 20-minute gap.
Got questions? Contact us and we are happy to help.