I just googled it for you and came up with a product review that also explains how to use it.  See here.

Have to say, what the ladies are saying about it isn't particularly good.  All saying it takes forever to heat the bottles.

I may not be much help but with ours we just plug it in then put the bottle in with a bit of water at the bottom and turn the dile to the correct heat.   We gave up on our bottle warmer pretty quickly and just ued the micowave.  Just make sure you shake the bottle well and mix the milk well after useing the microwave.   

this website http://www.boots.com/shop/product_details.jsp?productid=1042088 may help.  from looking at the picture it looks like our so just put some water in the warmer then the bottle and turn the dile to the correct temp.

Do you know the brand?  I had one that I had to put water in it and push a button for it to warm the bottle.  Pic would help to see what it looks like