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Issue description

In the section `pr01s03`, there is wrong catalog source in the all subscriptions yamls. There is `source: redhat-operators`, however, the all operators are in the `ossm-catalog` catalog source, so the example files should have `source: ossm-catalog`.

The problem with the whole pr01s03 chapter from my POV is that it looks like an informative appendix and should be at the end, not at the start because it can be confusing for the user/learner since all those steps/information will be learned in the next chapters.

Steps to reproduce:

Expected result: