as long as the shoes are scrupulously clean its very easy, if they have any grease on them the it will be patchy. You also need to bare in mind what colour they are now> If there is any stitching which might be made of something that wont take the dye?
Dylon make a special satin shoe dye or the multipurpose dye will be suitable and they have a bordeaux colour or you can mix to achieve the right colour.
Basically you get the die, mix it with very hot water (fixes the dye), about a pint and keep adding the dye until the couolour is right. Then you sponge the dye onto the shoes.
You can keep repeating the process over a few days (needs at least 16 hours to dry out properly and give you a good idea of how they look) but the result isnt colourfast, so keep them dry.
Im sure if you go to the dylon website or your local haberdashers ad they will give you the right equipment.