How do I make a Dummy esp - For loading custom BSA's which just replace vanilla resources as replacers (and so they can be overwritten with loose replacers if needs be which now load last)

Is it just a case of for example creating an empty text file, and calling it by the same name as the BSA, but with a .esp file extension ?

Or does it need to be generated by the Creation Kit, with Skyrim.esm as a master ?

If its the latter - A walkthrough would be very much appreciated (noob Creation Kit user )

A renamed .txt won't load as it doesn't adhere to a plugin's file structure. You can simply make an empty, masterless .esp with the CK (nothing checked in File > Data) and ensure it'll autoload the BSA by virtue of its nomenclature.

Alternatively, you could probably just name the BSA 'Update - Whatever.bsa' and do w/o the 'dummy' plugin by piggybacking Update.ESM.

Thank you JustinOther, made an empty masterless esp which will auto-load the bsa with the same name.

I didn't know about chain loading bsa's with an esm and extended naming .. sounds like it would work (in fact I am pretty sure I have seen that mentioned in Oblivion topics too) - But decided not to in case update at some point in the future gets dropped, which also gives me freedom in the load order department too among other bsa's, with loose files still overriding them.