Hi Cesarious
Thanks for your interest. Dwarven Forge is a great company for this kind of set-up. Their products are pretty expensive, though. You can check it out on their site. The basic dungeon tiles (also called game tiles) are a good way to start. If you cannot afford this investment, crafting things yourself is another option: check out YouTube channels of DM Scotty, Wyloch and Black Magic Craft to build scenery from mostly scrap.