Adding all the steps and making use of sphinx tabs.

### Where should the content be added?

https://conda-forge.org/docs/maintainer/adding_pkgs.html

### What should be added?

**A thing that I have observed is that:**

As a reader for 'getting started' I kept jumping from link to link without completely reading all the instructions.

For example: the sentence - Look at [the example recipe](https://github.com/conda-forge/staged-recipes/tree/master/recipes/example) in the [staged-recipes repository](https://github.com/conda-forge/staged-recipes)`
That's the first instruction I read. I clicked on the link and I thought to myself-- "Okay. Now what?"

And I am assuming there are many readers like me (more experienced ofc!) who fall into a pile of mishaps they could have avoided if only they had read all the instructions.

**A possible solution**:

Shall we put up the instructions on going around Grayskull, CRAN (Not my forte!), and the example recipe within this document itself?
To neaten things up we could make use of [sphinx tabs.](https://sphinx-tabs.readthedocs.io/en/latest/)

### Additional information

This issue is a continuation of my comment under PR #1698
(I'll create a PR of what I have in mind.)