Do you have the large insulated bucket, and the smaller bucket with a metal handle that sits inside?
If you have some, thread the heating element through a piece of plastic pipe first, then thread this along to the plug end (to stop the lams chewing the power cable). If not, just be aware this can happen.
Put the heating element on the very bottom of the large insulated bucket, held down by the black clips which will be stuck to the bottom. Keep the cable up the side of the bucket, with the plug out over the top. Some have a groove to slot it through, some don't.
Fill the smaller bucket, which will contain the milk eventually, to the top with warm water. Tip this into the large bucket ontop of the heating element, which will probably be completely submerged. If you have some, add a couple of drops of Hibiscrub or similar to the water.
Give it a wee while to get to the temp you want.
Make up the quanitity of milk you want in the smaller bucket, then pop this inside the larget bucket - it just sort of floats on top of the water. Make sure the rim of the bucket goes under the wee metal pipes.
Attach the plastic tubes to the metal ones and sit them into the milk.
Put the teats on the outside.
Not sure if that is what the manual says, but works for me.