Make screw holes in a item

I have trouble inserting screw holes in a model.
I want a finished item like picture 1.
Picture 2. shows the individual groups in the drawing.
Picture 3. shows a warning I get in the Slicer program (CURA)
Picture 4 and 5 shows gaps in the workpiece when it is sliced.
I have used the “Intersect Faces - With Model” function to insert the cylindrical holes.
How do I draw this item correctly so that it can be sliced / printed without holes?
Since I’m pretty new to Sketchup, it would be nice with a step by step guide, or a video.
5 - Sliced 02
4 - Sliced 01

Holder til ukrudtsbrænder 03 - first try.skp (1.3 MB)
Holder til ukrudtsbrænder 03-new.skp (1.3 MB)

See if this model works for you and see how it compares to yours.

Holder til ukrudtsbrænder 03-newBox.skp (99.5 KB)

Are you trying to create raised screw bosses or do you want them to be counterbored?

Yours is in the rear.

I think Box beat me to the draw!
Here’s my version…
Separate all of your ‘containers’ - don’t nest them.
Ensure that the holes you have punched into the main forms have internal faces - these maintain the main objects’ ‘solidity’…
Purge unused…
Holder til ukrudtsbrænder 03-newTIG.skp (147.2 KB)
Dave’s point about raised or countersunk bosses also needs addressing…
I assumed they were recessed…

Everyone beat me to it but here is my tutorial. Click in sequence on the scenes tabs of this SU file for ideas.

Bolt holes in a cylindrical piece.skp (440.7 KB)