Les, on a new venue that holds carp and tench, I always start at the base of the first shelf, just out from the bank.
Plumb up with a SSG shot on your hook, and find the depth just in front of your feet.
Walk the rig out until you find the edge of the shelf where it begins to drop off and deepen.
Keep lowering the float in at spots six inches further out each time, altering the depth if the float sinks under.
When you have had 2/3 drop ins without having to deepen any more you have found the base of the first shelf, its usually 1to4 mtrs out from the bank in stillwaters.
Lay down a carpet of inert feed, casters, dead maggots, corn or chopped meat at this point and fish a large bait over this 'dining table'.
Works for me most of the time on new waters, carp and tench patrol these shelves as food naturally gathers at the spot where the shelf meets the level lake bed.
Here's a sideways view in text.
TTT.....X
.....................Yzzz..........
If you were sitting on top of the TTT of my rather poor diagram, the dots following the Yzzz would represent the top of the shelf under the water, at X the shelf drops off and deepens down to Y, zzz is where you would lay your bed of feed, and place your float rig.
At some point patrolling carp and tench will find your bed of feed and often give away their presence with bubbles rising to the surface as they get their heads down.