I think if tou wanted to do that sequentially or make sure that every chair is different it would need more work. But the idea is just make an array of staticmesh and assign that in your staticmeshcomponent, you can do that in the construction script in the blueprint or on your construction method in your class, or in yhe postInitializeComponents function or others (please read ue4 doc of actor initialization step). I think i have seen some implementation of this in youtube. Just search crowd system test ue4 in youtube. I think in some videos the author to this mechanics to change the mesh