You also need to prepare for the dress for yourself and the dresses for your maid of honor and brides maid. Usually this is done talking with friends and family.
The men need to get a tuxedo. Usually you find a tux shop and they take care of the rest. Only instructions you need to give to the best man and grooms men is the location of the place.
I don't know the rule for who pays for the tux or the dress. I've seen it both ways. In some weddings, the people wearing the dress or tux pays for it, and in other weddings, I've seen the wedding couple pay for everything.