Unity Android File Download
Whether you’re building an android application in unity or programming it from scratch, you need to set up the android software development kit (sdk) before you can build and run any code. Build your dream game, and make it a huge success. /storage/sdcard/downloads tho, that varies on each phone, so you need a way to get the androids internal storage path. After this my app will use those files.
A unity id allows you to buy and/or subscribe to unity products and services, shop in the asset store and participate in the unity community. I'm working in unity 5.6.0 at a system for android, what at first launch is downloading some files (a.txt and 4.mp4). For my phone download folder is located under: Complete unity game development course for beginners