Commands syntax:

From To CommandName Parameter1 Parameter2 …

Parameters:

From, To - frame index range for which the command will be executed
CommandName - name of the command (Move, Rotate, Scale etc.) 
Parameter1 Parameter2… - command parameters

Numbers, variables and expressions (functions, arrays, etc.) can be used as parameters.

Examples:

Numeric parameter:
Each step from step 0 to step 50 shifts the object by dx = 1, dy = 2, dz=1 relative the current position

0 50 Move 1 2 1 

Variable parameter:
variables must be initialized in custom script

0 50 Move X Y Z 

Custom script:

Dim X,Y,Z
x = 1
y = 0.5
Z = 0
Sub StepCustomAction
'// TODO your code
end sub

Parameter as expression:
The actor will be moved along 3D spiral

0 50 MoveAbs X y(X) z(X)

Custom script :

Dim X
X = 0
Sub StepCustomAction
X = X + 0.5
end sub

function y(x)
y = sin(3*x) 
end function

function z(x)
z = cos(3*x) 
end function

Using arrays:
This command will replace material of the actor graphic with the value retrieved from the array.

0 50 Material Name

Custom script:

‘ initialize materials array
Dim Name
Dim Mats(3)
Mats(0)= "Wood\Dark Wood"
Mats(1)= "Wood\Varnished Dark Wood"
Mats(2) = "Wood\Varnished Redwood"

Sub StepCustomAction
if(StepNum < Ubound(Mats)) then
Name = Mats(StepNum)
end if
end sub