I was wondering how to bump my post once a day, I get told to do this but I don’t see an option for it. 

There is no bump button. Players typically just write “bump” once every 24 hours as a post, to indicate that they are indeed bumping

Below is a previous auction of mine, as an example. I bump my thread once every 24 hours. Hope this clarifies what bumping is / how to do it 

 

https://pokemonrevolution.net/forum/topic/236748-ada-shiny-scizor-auction-closed/

Hi. Thank you for contacting us about your issue.
 

As the Player @Lacomus mentioned very well, to bump a Thread, you simply type as reply in the thread "bump", only once per 24 hours is allowed per thread. 

We hope the information will be useful. I will now lock this thread as the query was resolved. Good luck in your adventures!

- Kubrick