Well, you need to create a equation type question.
From there it depends a little how your question is structured (what question code and subquestion code you gave everthing).
Let's assume the question code is "Q1" and the subquestions are "SQ001" to "SQ005", then you should be able to write an equation something in this line:
Code:
{sum(Q1_SQ001, Q1_SQ002, Q1_SQ003, Q1_SQ004, Q1_SQ005)}
This should sum up the values of the 5 subquestions that you created. Give it a try and see if it works out. This is how I usually write equations. Because if you write them complete and something goes wrong you don't know where the problem lies. If you don't get the some of the answers correctly you know that you need to check on this code first.
Once that works you can try to write the suggestions. This is not really much different to what Joffm was showin with good, etc. You just have a few more things to check.
If the sum works you could create the first check. Something like this:
Code:
{if(sum(Q1_SQ001, Q1_SQ002, Q1_SQ003, Q1_SQ004, Q1_SQ005)>30, "Extremely satisfied","lower"}
This should give you a text "extremely satisfied" for scores from 35-31, for everything lower it should give you "lower". Again, this is just a step by step test, if your equation is going fine so far. If that works you continue from there.