that download doesn't even work lol. windows just yells at me when I try to open it
anyway you should try looking at the txt file. the samples section has either #default or #optimized (not both though). if there's another line that has a word with a # before the closing bracket (ex: )
Code#samples
{
#optimized
#customs
}
that means "customs" is a new sample group and you 1. need to add its samples to a new folder with that name, in the samples folder, and 2. probably have a txt file called "PASTE INTO addmusic_sample_groups" or the like, which needs to be pasted into, you guessed it, addmusic_sample_groups.txt
sometimes someone will define their samples manually in the port though, which looks like this:
Code#samples
{
#optimized
"sample_folder/sample-1-name.brr"
"sample_folder/sample-name-2.brr"
...
}
in that case, there's probably a folder in the zip with the samples in it (its name in this example would be "sample_folder"). if that's the case then just move it to the samples folder, so the path becomes "(AMK folder)/samples/sample_folder/(all of the samples in that folder). if it just has the names of the samples and no folder name before it then you just put the samples into the samples folder.
hope this was helpful as I can't really look at the port myself
(EDIT) I was able to open it using a different computer which has 7-Zip installed. He defined his samples really weirdly to say the least. You want to put the samples in the zip straight into the samples folder, and probably add #optimized to the sample group. I don't know what errors you're getting so I don't know what needs to be fixed lol, just grasping at straws here really