nothing on the back of the cover - there is a rough guide in the manual, but there are more fuses in the fuse box than shown in the manual

 

Do you not have a guide to what the fuses are in your car? normally on the back of the cover

 

Up to 20amp, but "select a fuse which is associated with a function within the vehicle which can only be used when the ignition is turned on." - "a switched power source." The fuse box diagram in the manual doesn't match the fuse layout in the fuse box.

 

What size fuse does it say to use?