Before we start, make sure you have CLEO installed for San Andreas and also make sure you have an 
Open Limit Adjuster installed for San Andreas.

Feel free to google search a tutorial on how to implement CLEO and/or Open Limit Adjuster.

If you haven't already, you MIGHT want to install the first Elvis Variation Mod of mine first, before installing this one. Here's the link:
https://www.gtainside.com/en/sanandreas/skins/145037-elvis-variation/

This allows for maximum Elvis variation when combined with this pack, so I highly recommend you install that one first.

Assuming you've gone ahead and installed the first pack first, then go ahead and follow this guide next.

Make sure you allocate 3 PED ID's for these in the Open Limit Adjuster ini file. (I will assume you
already know how to do this, so I'll leave this up to you without explaining it further.).

Now, you have to follow these steps EXACTLY for it to work:

1. Add the contents of the "add to gta3 img" folder, to the gta3.img archive using an IMG tool, then rebuild
the archive.

2. Go to your game directory, into the "data" folder, find and edit "peds.ide". Find the area where it says
"#---ADD NEW PEDS HERE", and put these lines under that text:

268, VHMYELV3, VHMYELV3, CIVMALE, STAT_COWARD, man, 170F,1, null,1,2,PED_TYPE_GEN,VOICE_GEN_VHMYELV,VOICE_GEN_VHMYELV
269, VBMYELV3, VBMYELV3, CIVMALE, STAT_TOUGH_GUY, man, 170F,1, null,2,1,PED_TYPE_GEN,VOICE_GEN_VBMYELV,VOICE_GEN_VBMYELV
270, VIMYELV3, VIMYELV3, CIVMALE, STAT_COWARD, man, 170F,1, null,1,1,PED_TYPE_GEN,VOICE_GEN_VIMYELV,VOICE_GEN_VIMYELV

You MIGHT HAVE TO change the "268" "269" and "270" PED ID values respectively IF you have other additional peds installed.
If you don't then don't worry about changing those values (again, I will assume you know how to handle this yourself).

3. In the data folder in your game dirctory, find and edit "pedgrp.dat". You will need to search for the line "# POPCYCLE_GROUP_ENTERTAINERS".
You should find a line that looks like this by default:

VHMYELV, VBMYELV, VIMYELV		# POPCYCLE_GROUP_ENTERTAINERS

IF you installed my previous Elvis Variation mod, the line will look like this:

VHMYELV, VHMYELV2, VBMYELV, VBMYELV2, VIMYELV, VIMYELV2		# POPCYCLE_GROUP_ENTERTAINERS

You need to change that line, to this line:

VHMYELV, VHMYELV2, VHMYELV3, VBMYELV, VBMYELV2, VBMYELV3, VIMYELV, VIMYELV2, VIMYELV3		# POPCYCLE_GROUP_ENTERTAINERS

Once you have replaced the line, save the file changes.

4. Load up the game and enjoy the increased variation of Elvis! They should all spawn in Las Venturas around the Casinos and such.