[steven114]

What do you mean by 'commands?' Are you referring to functions? Or are you referring to the autonomous program provided by FIRST? If you're talking about built-in functions, then you certainly can! The basic format of a function is this:
(replace the items in square brackets with the proper keywords)

[returntype] [functionname]([argtype1] [argname1],[argtype2] [argname2]...){
/*Your code here*/
return [result];
}

For example:

double squareit(double numberToBeSquared){
return numberToBeSquared*numberToBeSquared;
}