Ok lets see if we can get you on the right track, I do not know anything about mach3 VB so bear with me.
So the first few lines looks like you are defineing some variables and getting the FeedRate
CurrentFeed = GetOemDRO(818)
PierceHight = -10.0
ProbeFeed = 1300.0
would become something like
local inst = mc.mcGetInstance()
local CurrentFeed = mc.mcCntlGetPoundVar(inst, 2134)
local PierceHight = -10.0
local ProbeFeed = 1300.0
Code "G90 F" &ProbeFeed
would become something like
mc.mcCntlGcodeExecute(inst,"G90 F"..ProbeFeed)
If GetOemLed(825) = 0 Then
Code "G31 Z-117 F" &ProbeFeed
While IsMoving()
Wend
Not sure what OemLed(825) is but you can combine the execution of the G31 and While is moving by using mc.mcCntlGcodeExecuteWait
if (what ever Oem825 is == 0) then
mc.mcCntlGcodeExecuteWait(inst, "G31 Z-117 F"..ProbeFeed)
else
--whatever
end
I watched the video and my sugestion is to write down a series of events/steps and then use the API Docs found in the docs directory for the commands to do each step as I have above.
Hope this gets you on track, but like I say I do not know mach3.
DazTheGas