Take away one empty deep and start them off in a single deep box with ten frames and the feeder. You are giving them too much space to rattle around in. Plus, then they'll be closer to the syrup.
Take off the top deep and put to one side. If any bees are on its frames, remove each frame and with a firm downward move, shake the bees down into the bottom box which has 10 frames too- the box you are keeping there, on the bottom board. One you are done you'll have one deep with 10 frames off to the side and no bees in it, which you store somewhere until needed. Don't add the second deep back on top until they have drawn comb on at least 7 or 8 frames of the first box.
Take off the top deep and put to one side. If any bees are on its frames, remove each frame and with a firm downward move, shake the bees down into the bottom box which has 10 frames too- the box you are keeping there, on the bottom board. One you are done you'll have one deep with 10 frames off to the side and no bees in it, which you store somewhere until needed. Don't add the second deep back on top until they have drawn comb on at least 7 or 8 frames of the first box.