When I first started with Heroku it did seem complicated and quite intimidating as to how it all works, but in reality it’s actually really simple and straightforward to work with. It’s often more efficient to just install the command line Heroku tool (Windows/Mac/Linux), and then log into Heroku through the command line. You can then run `heroku create` to create a new .herokuapp.com subdomain. If you want to name the subdomain, you can just run `heroku create jack` to get jack.herokuapp.com (if no one else has, of course).
Heroku then behind the scenes adds a new Git remote, and to push to Heroku you simply need to run `git push heroku master`, and Heroku does the rest.
If you’ve got a small app you need to show someone, or test, I really can’t recommend Heroku enough. The free plan has some limitations (in terms of load/concurrency/etc), but for demos it’s usually sufficient. Production pricing is granular and on a pay-as-you-use basis.
If you’d like to try it, I recommend the Heroku Quick Start guide, as it contains all the information you’ll need to get something online.