Once the function is dot-sourced, you can call it.
So you do
. ./FolderByPath.ps1
$folder = Get-FolderByParh -Path "LTX01-G8/LTX-Servers/LTX Servers 0000 - 0299/Linux"
Get-VM -Name YourVM | Move-VM -Destination $folder
This will move 1 VM, called YourVM to the folder.
Note that you have to do the dot-sourcing only once in your session.