I have not figured out how to concantenate text variables, increment/decrement in short notation and using global variables.
Concatenate
text3$ = text1$ + text2$ ' "add" as many as you want
Global Variables use SHARED with DIM or REDIM:
DIM (or REDIM for Dynamic Arrays) SHARED x$, arr$(1 to 60), ...
STATIC in a SUB will preserve value between calls to that SUB (I consider that a little more advanced).
increment/decrement in short notation
Not sure what you mean
x += increment ' <<< does not work in QB64