No account needed. From github you can install the Obtanium .apk from the releases section. Valdium(browser) doesn't all installs, so you will be prompted to enable that. Once obtanium is installed, it gets a little easier because you can search and keep a list of the apps and perform updates and such, but really all it is doing is giving you a way to manage downloading and install ing apks from the various sources it supports. The settings in obtanium will seem confusing. "Usually" you can ignore most of them, but occasionally if you want to get specific about versions or prelease installs and such it lets you tweak it.

And please ask away, it can be an up hill battle at first. I came from iOS as well but am technical, and even still I found myself craving the ease of iOS. Don't get discouraged, its worth it.