Alright you need to install git and make a repo and an initial commit to get the code into git.
After that you need to make a github account and a repository there.
Then you make a keypair on your computer and store the public key in the github repository. This will give you privilege to push your code to github.
Then you add github as a remote repository to your git config on your computer.
Then you push it.
There's apparently a github desktop client which might make the entire process almost automatic so you should probably start from there. I haven't tried it myself, though, but I'm happy to help if you have questions.
I recommend you start with some test code and try with that first so you don't accidentally the Dragon_Quest code.