I am guessing your World has a similar arrangement to the one we had (W9933).
There is a metal plate on the leading edge that covers up a notch that hooks over the pivot pin.
So to reveal this take the boat off the trolley and get the boat onto its side, with the mast up. Usually this is fairly stable and the jib halyard to a fixed or heavy object will hold the boat in this position. NB Don’t use the main halyard.
With the board up you should be able to remove the screws fixing the plate, then the plate.
Then lower the board and you should be able to unhook it from the pivot.
Remove the board.
For the resistance, there is usually a “brake” on the centreboard on the upper edge – a short piece of tube clamped to the edge of the board and hence pressing against the sides of the centre board case. In theory adjusting the clamp will increase or decrease the resistance.
If that is missing replacement is available from pinnell and bax.
Hope that helps.