Set a lower boundary for Objective Value in Optimization Live Editor

Greetings everyone

I am using the optimization live editor, with a neural network function. I have 21 input data and 1 output, And I am using GA to get value of the 21 variables for the minimum value of the outcome, but I am always getting a negative value, that not works for this particular problem, I need to set lower a upper values for each of the 21 variables and I need to placed a >= 0 value for the output, thanks for any help