All I'm using Ae CC 2017, but all tutorials I've found are for older versions. How do I render a lower third output as an animation? I need it to be transparent in video.
Rendering hasn't changed. The easiest thing to do is to use the Lossless with Alpha stock preset in the Output module. You'll find it by simply clicking on the little arrow next to lossless.
Don't expect a lossless file to playback smoothly. Don't expect to have small file sizes. Do type rendering in the search help field at the top right corner of AE and study up before you start monkeying with the controls. If you are going to work in video you MUST learn about formats, rendering and compression. Otherwise you have to use the presets that Adobe supplies and live with the results.
One more thing - most YouTube video tutorials are junk. You need to vet your trainers. The easiest way to find folks that know what they are doing is to use AE's search help function or subscribe to a well respected tutorial series or buy a well respected book on AE.