Same speed on all machines and Tweening

This is the first time i do something like this, i am in the middle of the development of my game and just now i am trying to make sure that the game runs fine on all machines, i have been trying to learn about this subject and it seems overwhelming, so, i found this code about fixed step logic and tweening on the code archives, if i apply this, my game will run ok on all other machines?, will i encounter problems with it as i go further in the development?, would i need to also do delta timing or something like it?, do i need to consider something else?, thanks a lot for your help.

This is the link to the code i found:
http://www.blitzmax.com/codearcs/codearcs.php?code=2039