Pick a name for a variable.
var: myVariable(0);
Set the variable equal to your indicator.
myVariable=myIndicator;
If your indicator is average(c,5) that part looks like this.
myVariable=average(c,5);
To call your indicator within a second indicator use it's name in the place you normally see close price. If your second indicator is an average of your first indicator it's...
average(myVariable,5)
That gives you a double smoothed average or a 5 period average of a 5 period average.
If your second indicator needs a name you will need 2 variables.
var: myVariable(0), indicator2(0);
myVariable=average(c,5);
indicator2=average(myVariable,5);
You can name them indicator1 and indicator2 or anything that makes it easier to follow. You can use numbers within variable names as long as it's not as the first character.
var: indicator1(0), indicator2(0);
indicator1=average(c,5);
indicator2=average(indicator1,5);