
you will need a slicker brush an undercoat rake large and possibly a matt breaker and or dematting comb.athere are lots of different ones on the market you just need to try different ones to see what works best for your self and the dog.
You might also find a coat conditionins or detangling spray usefull.
Start at the back end of the dog by lifting up the coat and work from underneath with a slicker and remove the loose undercoat the rake will remove this too but I always start with a slicker.Be carefull with all brushes and combs that you do not DIG it in to the skin by using short,flicking strokes with the slicker and do not pull too much with the rake. If it sticks there may be a tug or matt so use the matt breaker or dematting comb. Be sure to be extra carefull on sensitive parts IE under the chest ,the belly and under the tail and inside the back legs etc.
Once all the matts and undercoat is removed you should be able to work a rake through with no problems.
If you use a conditioner or detangler spray a little section at a time by again lifting the coat and spraying it through the coat then start brushing. Remember to look for cuts ,rashes etc while grooming .
you should buy a book on grooming or go to a proffessional groomer for advice to help keep you right.
Hope this is helpfull to you.