In binary Genetic Algorithm how we can set multiple variable limits ?

I am beginner at the area of optimization. Normally, I download the GA, PSO codes from internet and then I modify them according to my problem and run it on Matlab.

In binary GA, most of the codes available in the internet does not mention about the variable limits, or the codes are given for only one or two variables. But, when we want to set multiple variable limits like upper and lower bounds of 10-20 variables. How to do it and how I should modify the basic crossover, mutation function for large number of variables. Any suggestion, help or example of codes will be appreciated.

[Ameer Hamza]

If you downloaded the code from the internet, then the most probable way to get help is to contact the developer of the code. We don't know the implementation of the optimization algorithm, and even if you post the code here, it will be difficult for anyone here to first understand the algorithm and suggest appropriate modifications.