It is a script that I use to setup my forks. You perform such a setup only once. This means you do not do it very often. I'm not an elephant, I don't remember commands I use rarely. I like to have these things in scripts.
Use the script by passing two variables: bash conf_fork.sh <ORG_NAME> <REPO_NAME> <MASTER_OR_MAIN>
For example. If you want to contribute to generator to AsyncAPI and you forked the repo, then run the following in your terminal in the root of the repository:
bash conf_fork.sh asyncapi generator master