How do I install modules and extensions?

[the vampire jack]

I copied the down load and placed into extension folder after that . Exited and updated fantasy grounds and i added the extension on that bottom right on load up but everytime i roll a crit it keeps saying error and a bunch of codes pop up

[LordEntrails]

I copied the down load and placed into extension folder after that . Exited and updated fantasy grounds and i added the extension on that bottom right on load up but everytime i roll a crit it keeps saying error and a bunch of codes pop up

I don't think you posted in the correct thread. This thread is about FG Classic, which was discontinued years ago. Unless you are using FGC, this is the wrong sub-forum.

If you are having trouble with an extension from the Forge, you don't need to manually install those. They get installed when you Update FG. For issues with such an extension, see the "forum thread" linked on the Forge page of the item.

If you are having problem with an extension from the DMsGuild, then you should contact the author in the manner the author states on their DMsG page.

If it's an extension from a thread on the forums here, you should post in that thread.