The Gog version is either Skyrim Special Edition (SSE) or Anniversary. So you have to download most mods from the Skryim Special Edition Nexus.

Fortunately most Skyrim LE mods are easily ported, if they do not require the script extender. I had ported a few mods myself and they worked just fine when I tested Skyrim SSE.

I'll have to look at Tokkimoon's Adoptable Children later on to see if it can be ported to SSE. But I still play Skyrim LE.