The balm works best when applied to a damp beard. For example, pat-dry your beard after a shower. The amount you use will vary depending on the length and style of your beard. I advise starting off with a dime or quarter size amount. Scrape that dime sized amount of balm out of the tin and rub it between your palms until it has completely melted. Rub the melted balm through your beard. Let the balm sit on your beard for a few minutes to allow your beard hair to absorb some of the balm.
What should you use to comb or brush your beard? Whatever works for you! Some say you must use a horn or wood comb and I say that isn't necessary. The most important factor is wide, rounded teeth in the comb. Do not use those small plastic combs that come in packs of 10 for $5. The teeth are too close and will rip out your beard hair.
I personally use a plastic detangling comb on my beard while it is still warm from the blow dryer. II get really good results with it.
The bottom line here is to use some beard balm, or oil and a wide toothed brush/comb to style it out.