SBK74 is right, while 'ignition' on during charging you toggle the mode switch to the right and hold it for a second. Then arrows appear indicating that you now can set the current - again with the mode switch. left for less, right for more amps.
Leave it at the figure you want to adjust, after a second or so the system has accepted it.
The message 'you can disconnect cable now' indicates that you interrupted charging e.g. by accidentially having pushed the menu button when the 'ignition' was on.
How many amps you should adjust depends on your electrical installation. A standard plug-in-socket in anmodern house installation (European standard) should have 16 A, but be aware that this is a short-time maximum. After talking to a certified electrician even 13 A could be too much - switching on another high power consumer could trip your safety fuse.
10 A should be very safe - that is the level I chose for me.
