Yep, 2.5 pounds will make you around 1 gallon of decent mead. Just add water until it hits around a gallon, plus or minus. Then pitch your yeast and let it go for a month. Doesn't need to be too complicated. On the other hand....
Many self-proclaimed experts would poo-poo the idea, but I like to heat treat my must (i.e., raw mead) at about 160 F for 10 minutes to kill any wild bugs, then cool and pitch a mead yeast or wine yeast. It's true you don't need to boil or heat treat, but in my experience, I had an unheated batch that tasted like vomit and had to be dumped so I vowed never to do that again. Then after fermentation is complete, add sorbate and prime as normal... or don't. Meads are traditionally uncarbonated, but I like a little fizz in mine.