I build a Tour with floor plan but I have problems with it.
1) The only way to see the floor plan is it to click "start opened", but if I close it, it is closed forever. The "map" button in the menu doesn't work and I can not find an other option to show it again.
Maps and Floorplans are different things.
You need to add a Floorplan button to your Control bar, or to use a Simple button or Toggel button plugin to control display of the Floorplan - se screnshot 1.
2) At first I placed the floor plan in the tour. Than I decided, to merge all panoramas in one group and to place the floor plan in that group. Now I have two floor plans and I don't know how to delete the first one (or the second one).
You can assign a Floorplan to the project as whole, or to a Group.
Configure the Floorplan plugin to determine what gets displayed.
Press Shift+Click to reset the floorplan graphic - see screenshot 2.
3) I set color to the hotspots on the floor plan and clicked "pause autorotation on hover", but they are still white and don't follow the command "pause". I How to fix it?
Hotspot colours are working for me. Have you associated your Floorplan hotspots with the appropriate hotspot styles - see screenshot 3.
I agree that Pause autorotation on hover doesn't appear to work if specified for a Floorplan hotspot, but you can instead specifiy that Autorotation is paused when the Floorplan is displayed in the Floorplan plugin parameters