Hi George,
almost but not quite correct It's best to give advice correctly.
Tab will only work, wenn a suggestion is already shown and then it will just fetch the suggestion to your cursor position.
If you want to force the editor to show suitable suggestions or completions, press Strg + Space.
@Edmund: check the settings in the lower right corner like George has suggested. If the hints don't show, most probably are they disabled there.
BR - Jörg