LyX, referred to as "The Document Processor" by its developers and maintainers, greatly simplifies the process of preparing documents with TeX/LaTeX, by hiding much of the details of its LaTeX beackend (which hides the pain of its TeX backend). It does however require users to convert LaTeX formats into native its native formats in certain case. This article provides some hints on creating a LyX layout from a LaTeX class.
The files I am adding are those provided by the AIAA for their publications; they distribute the files:
The desired LaTeX class can be added to either the local TeX tree for all users or to an individual user's TeX tree. It is however easire to add it to an individual user's tree. In either case the location of the trees on the filesystem must be determined.
The texmf.cnf file specifies the locations of these trees using the environment variables $TEXMFLOCAL and $TEMFHOME. If these are not set, they need to be set. To find the location of the texmf.cnf file use the command kpsewhich texmf.cnf. In Fedora 28 and Manjaro neither of these variables are set. I set the $TEXMFHOME variable by adding export $TEXMFOME=~/texmf to my .bashrc file. This is necessary so that latex and tex and lyx can find.
For Lyx to be able to use this newly installed LaTeX class, a corresponding Lyx .layout file needs to be created with the same name as the class. Again I chose to make this file available per user instead of systemwide, placing the file in ~/.lyx. The .layout file can also be conveniently be placed in the same folder as the document being prepared.
I found the it difficult to add all of the neccessary elements to the layout file as I didn't have the necessary knowledge, but produced a working layout file conforming to the publisher's requirements using the following procedure, which was made possible by the fact the AIAA distributes a sample document that uses the class and bibliography files.
LyX Configuration Manual Section 5.