How to find the url of your github pages
If you've activated GH pages then you should see this Github pages link on your repo.

Click on this link. Then click on the view deployment button.
That will take you to your deployed GH site.
OR
You can convert the url of the repo.
https://github.com/jamischarles/til
would map to (assuming there's a github pages site pointed there)
https://jamischarles.github.io/til
So the formula is
https://github.com/[github_username]/[folder]
to
https://[github_username].github.io/[folder]