Help with mods use please...

[Bonefish]

Hi all. Can someone please give me simple and clear instructions on installing new mods (new races mainly).
I have just got se4 after years of playing se3, and find that Im not too sure were exactly to place the unzipped files of various types. Ive read a few things but they seem to conflict. Are there different ways depending on the modder? The race mods Ive seen are of very high quality, and my hat goes off to all you modders who make games like even more fun and unique for those of us with no time or know-how to do it ourselves.
Many thanks in hopeful advance.
Bonefish.