On another computer the icon appeared automatically and I reserved the download OK.
On this other WIN 7 computer altho I have the 2 apparently necessary updates KB3035583 and 2952664 there is no WIN 10 icon appearing after at least 1 day. There are no compatibility messages appearing as had appeared on another computer because of lack of HDD free space.
So what can be the cause of this 'glitch'? Thanks for advice.