Sign up for a Github account by visiting https://github.com/
Create a new repository with a short name
Click Get started by "creating a new file"
4. Enter your file name as poolMetaData.json and paste in your json content.
5. Click Commit new file
6. Click your new file's name
7. Click on Raw button
8. Copy the URL into your clipboard
9. The URL must be shorter than 64 characters. Use https://git.io/ to shorten it.
10. Use this tinyurl URL
--metadata-url in your stakepool registration transaction.