Rather long post. TL;DR at bottom.
I've been going through a back and forth with the "How-To" tutorial video on the official website, trying to make it work through CurseForge, through original/manual means of the folders with downloads in base Minecraft, etc. And since I've been pulling my hair out on trying to figure it out for almost two days- along with Google not yielding any answers for my issue- I came here hoping someone could help me. 
My problem lies with the mod just not working a lot of the time, either by standalone or with other mods in CurseForge. I have a modpack that FTF is in that I've gone through so many times to find out the issue but nothing seems to help. [Meaning that every time I go through it, I usually have the FTF mod active alone in the list and nothing else first to try to debunk the means of why it isn't working correctly.]
TL;DR:
- In CurseForge I have had it work sometimes but never fully since it gave the mods "Error" message that's part of the pack upon loading a new world and then sometimes not.
None of the items that are part of the mod show despite the '/datapack list' command saying it is running, which is reoccuring. - Doing the step by step with the video on the official site "works"
but none of the items show as said above,no world events occur, and Herobrine never appears. Both with CurseForge and base Minecraft mod folders. - Opening base Minecraft with the mod and not with CurseForge is just an incredibly laggy world- as to why I'm still not sure.
- I have never gotten an error/crash message from this mod or any other mod within the modpack so I can't give any details on that.
- New and old worlds with the mod give no difference of the mods performance.
This might be a very simple solution to everyone else familiar with the mod but I just can't figure it out myself by any other means.
Am I doing something wrong or perhaps missing a very obvious step?