Can someone explain how to use the support option and explain theory of use.
Thanks
Lou
The support is generated automatically if required. The default setting of 30 degrees is pretty good for most prints.
It is used to support overhanging parts of a print. Look at some of the parts I printed and you’ll get an idea of what I mean. Someone else may be able to explain better though. 
Think of it like this. If you were to print the letter “T” standing up, when the printer got to the crossbar section of the T, it would extrude filament. Without support the filament would just fall down since there is no support to hold it in place. With support, the filament would be held in the proper position until it cooled and hardened. The software, when preparing the file for printing takes into consideration the shape of the item and would add support to the print so that when it got to the crossbar it would be supported until cooled.
Normally the angle indicated is the maximum angle from horizontal that the support material will be printed. Increasing the value will add support material and increase printing time. Decreasing the value will reduce support but may cause parts to not print right. There may be times in order to get the perfect print for a particular item that you need to increase the number, and there may be times when you can get by with decreasing the angle to get faster prints and use less filament. Depends on the part and your intended use. I normally kept my Afinia between 20 to 30 degrees, but had to change it on occasion depending on the part. So far the support material on the Zortrax has been very easy to remove, so I would not hesitate to increase it if I felt the need.
The orientation of the part to be printed can also play a role in the support. Suppose you took the same “T” but printed it upside down so the crossbar was against the platform. It would not need as much support at that point since there is no overhang. Same thing with a “U” shaped part such as a bowl or container. Printed with the base on the platform does not require as much support as printing with the bottom of the “U” on the top.
I edited the first part to make it easier to understand. I would also like to add that I normally determine the print position by the forces that will be applied to the item rather than just trying to reduce the amount of material used. An example of this would be to print two cylinders, each the same size (about 3mm to 4mm in diameter and 50mm to 60 mm long). Print one standing up like an “I”, the other laying on its side like “_”. Then break each one like you would a pencil. The orientation of the layers makes a difference in strength depending on the type of forces applied and their direction. But this should really be another discussion. Just mentioned it here so that you would know there are other things to consider when setting up an object to print along with the amount of support used.