Are you possibly new to RoboHelp? I ask, because it sounds like you may be.
Apologies in advance if you are already aware of this. But RoboHelp is not like some software similar to say PowerPoint, or Captivate, or TechSmith Camtasia where you have "assets" that are stored in a library and ready for use in a project.
Now, having said that, I'm aware that older versions of RoboHelp offered a collection of assets (mostly small images) that were installed along with RoboHelp and could be easily included in projects. But you had to be made aware of them and know where to look to find them. But they had to be specifically added in order to be part of a project.
To my knowledge, the new RoboHelp 2019 does not include any such assets.
Hopefully this answers your question. But I'm not certain it will. If you need more clarification, please reply back.