Bicycle Tutor

My Ultegra shifters are loose and flap annoyingly when I go over bumps. I haven't taken these apart before and am hesitant to undo many screws. Anyone know how to tighten these up or have a helpful link?
Thanks!
TZ

This is Shimano,s instruction sheet for Ultegra STI.
http://techdocs.shimano.com/media/techdo...http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_6K20A_001/SI_6K20A_001_En_v1_m56577569830
Is it just the lever bit that's floppy or the whole unit?
If it's the whole unit :-
If you look under the hood (rubber), on the "outside" of the shifter, there is a dimple. Lift the rubber slightly and you should see the head of a hexagon socket screw. Take the appropriate size "Allen" key and tighten this. This clamps the STI to the bars.
If it's just the lever that is floppy then there are springs that hold the lever against its stop.
Maybe these are broken or need cleaning.
There are maintenance instructions on the Shimano sheet which may help. You could print these off for future reference. I put all my info' and instruction sheets in a file which I can refer to later.