README updated for initial setup and installation
- [ ] closes #xxxx (Replace xxxx with the GitHub issue number)
- [ ] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [ ] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

Thanks for the contribution @davoodalavi, but we try to avoid merging pull requests that mix different fixes and introduce somehow arbitrary changes.

What I recommend is that you open an issue if there is something that you want to discuss. For small changes feel free to open a pull request, but do not mix things as it makes reviewing complicated, and also managing changes in pandas and keeping a clean history in case of issues.

In this particular case, if you think that there should be blank lines after headers in the README, that should be a separate PR from the rest. I don't think we'll merge such a PR, as the GitHub markdown format supports not having it, and seems opinionated to have them or not, so it seems to just introduce noise and add no value (noise by having to review more PRs, having a longer history, changing what `git blame` returns...

For the other comments, they also seem opinionated, some users will find it useful to have information on how to create virtual environments, while for others it's obvious, and others won't use venv but something else. I personally don't think we should have a too verbose README as we already have a two installation instructions pages, one of them very verbose.

So, closing here, but as I said, if you still think something should be changed, please open a new PR, but in an atomic way (addressing a simple topic at a time, not mixing different things). 