As a point of interest, if you place the LM324NS.mod file in the .sub directory and modify the LM324NS.asy symbol with the Symbol Attributes Editor so the SpiceModel attribute is LM324NS.mod, then you should not need an .include or .lib statement to use the device in simulations.
The standard.bjt is already a text file, just paste into the folder where the current folder is located. [ save the original standard.bjt as a back up in case you mess up]
the other option is to find an LT op amp that closely matches the LM324 and use that one. that way you can select it from the listing. you can save a symbol file in the op amps symbol directory, but you still have to include the model file. you will have to read the model file to get the pinout, then you can create a .sym file from one of the generic op amp symbols.