Unscrew the new plug and remove the cover.
The layout above is the layout of a UK plug.
The fuse is on the right hand side and sometimes depending on the make of plug is best removed to allow access to the terminal.
The terminal on the bottom right next to the fuse should be connected to the Live (Brown) cable.
The left hand terminal should be connected to the Neutral (Blue) cable.
Finally the top terminal should be connected to the Earth (Green and yellow) cable.
A simple way to remember the correct positions of the wires is:
BL - Bottom Left - BLue
BR - Bottom Right - BRown
After connecting the wires, the appropriate fuse should be replaced and finally the flex cable should be clamped in place using the cable grip at the bottom of the plug.
The cable grip is sometimes a screw down clamp and in other cases the plug has two flanges which the cable should be pushed into to make it secure. It is very important that the cable flex is secured in this way to make the plug safe.
The device to which you are fitting a plug to, usually has an Earth wire (Green and Yellow).
However some devices are double insulated which means they do not require an earth wire.
Most modern new appliances now come with a moulded plug, this can not be opened. If you need to replace the fuse in a plug of this type, the fuse cartridge in the centre of the pins of the plug can be levered out with a small screwdriver.
A fuse of the same rating should be used to replace the blown fuse.
It is importantto ascertain why the device blew a fuse in the first place.