This worked example will walk you through the insertion of GELLO code on decision arms for the '? anaemia' decision in the GORD (Gastro-oesophageal reflux) example. A GLIF file is provided (GORD_start.GLIF) that is suitable to use; along with some test patient data in xml format.
Anaemia is a low haemoglobin (hemoglobin) level, and in the GORD guideline example represents a compelling reason for early endoscopy, as there may be a cancer of the esophagus or stomach causing the reflux symptom.
Open and unzip the attached folder. Open the GLIF file with the GLIF Editor.
It opens at the "top level" guideline. There are three sub-guidelines and they can be accessed by clicking through the guideline itself or by scrolling down on right hand side (RHS) of the menu bar:
Go to the "consider early endoscopy" sub-guideline.
Notice the decisions, as elsewhere are pink. They are not automated as yet. So we will do that for the anaemia decision.
It's good (for me anyway) to write GELLO for GLIF decisions against loaded patient data. Let's load some data. This is in xml format and you can look at the test data in notepad++ as well if you like.
Go back to the top level guideline then go File, Load xml Test data. Choose test.xml. Go back to the "consider early endoscopy" guideline.
Now click on the Allow modifications button 
( count six in from the LHS of the top menu.)
Position the cursor on the "yes" arrow coming out of the "Anaemia?" decision such that you get a little hand with the finger pointing onto the arrow. Double click and go Edit:
