This question looks like it is about the game EVE Online.
You can set this by not using the default mining bot but this mining bot instead: This mining bot for EVE Online contains more features and also has a configuration section to support picking mining sites with bookmarks. On the description of this bot I see it asks you to enter the name of a bookmark of your preferred mining site:
You can download this bot and then open it in the Sanderling app via Automate Something Else → Load Bot From Local File.
For configuration of bots in the Sanderling app, we have this guide: How To Configure A Bot