I want to use one of the potentials on NIST , but how can I implement them like Al-Au-Si

Given one of the potentials in the link, I have the potential’s .txt file.
But how to use it in LAMMPS script is not explained.
should I just say:

pair_style adp
pair_coeff * * Si_Au_Al.mod.txt Si Al ??

Because I don’t have Au in my system…

resource: Interatomic Potentials Repository

This is not a well posed question (how can just an URL be that?). All relevant information should be provided in the database. So either you are not reading it properly or you need to contact the database maintainers ask to include missing information. Given the format of the post, I would suspect the former is the issue, i.e. this would be a so-called PEBCAC issue.

Actually I decided to this way and it works:
1- you should have 3 atoms in your data file but you will never insert Au so that wont be a problem.
2- you can use it this way otherwise it will give error:
pair_style adp
pair_coeff * * Si_Au_Al.mod.txt Si Au Al

3-Note: the other thing is after you inserted a vacuum manually in your data file, you can change back to P P P periodic conditions so it will not shrink before you start deposition. Otherwise it gives “Deposition region extends outside the box” error.