Teleporter is building, which can be built by Engineer. After it charges, it started to fastly spin, meaning it's ready to teleport someone. You can also telefrag with it. the teleporter is building which can make you make an warp jump. After it teleports someone, it will stop spinning, meaning it's charging for another teleport. The entry teleport will bring you onto exit teleporter(they are both connected, and it's important to build entry and exit teleporter)