AD&D Battlesystem Skirmishes Miniatures AD&D 2nd Edition 9335 TSR 1991
This book, a full-scale revision and expansion of the rules in the original Battlesystem Fantasy Combat Supplement, gives you all the information you need to set up and play battles with miniature figures.
These rules can be used without the AD&D game books, but you can also convert characters and creatures from an AD&D game campaign and use them in Battlesystem scenarios.