You will want;
hay feeders,
water troughs or licks-its, mineral feeders, all wall hung (need to be separated by several feet at the least) or free standing if a double sided hay feeder. Depending on the size of herd you might leave most of the space a single open area, the goats will love that, whether meat or dairy goats. I would also include a separated area, that is completely closed off from the goats for storage of grains, treats and hay, a few stalls for separating when necessary (mother and new born, sick goat etc.) and maybe a space to do hoof trimming. If they are
milk goats, I would have the milking station in a different place than inside the barn, perhaps an add-on type of room for that. If they are not going to be able to go outside as they want, then definitely build a play ground in the barn.