Here is what I used to help solve the user input problem.
https://docs.unity3d.com/ScriptReference/Input-inputString.html
You don’t need to use GUIText. I just used a class string variable to store the input until enter was pressed at which point you can set/save the value and move on. Remember though if doing that you need to do special conversions to change the string variable to integer.
Feel free to have a look at my code if you like:
http://pastebin.com/RNVY9KcB