How to join three 1d arrays to become a new id array.
array 1 = 1 2 3
array 2 = a b c
array 3 = A B C
new array = 1 2 3 a b c A B C

The function is called build array.  Grow it to have three inputs
and the output will be what you want.

Greg McKaskle

Use a "Build Array" with your 3 arrays as inputs, enable "Concatenate
Inputs" from its pop-up menu and you'll have the expected result. In
case you are performing this operation inside a loop or dealing with
big arrays, you may try to find a better solution (regarding resources
usage).

Hope this helps

You can accomplish the same result in a loop by using Shift Register
with Build Array function.