Fork this repository into your own account (if you use as destination a repository named USERNAME.github.io then your url will be username.github.io, else username.github.io/REPONAME/).
Modify _config.yml with your data.
Use the files inside of the /_posts/ directory as templates to modify and create your own blog posts.
Delete images inside of /assets/img/posts/ and upload your own images for your posts.
Make sure Github Pages are turned on in the repository settings, and pointing to the main or master branch (where you cloned this repo).