Adding MA of OBV condition to existing EA.

Just starting to play with MQL5 and this is an educational exercise for me so I can see how things are done in the source code:

This one is about adding an extra buy/sell condition to EA.

To a simple existing EA based on MA cross and PSAR with some money management functions etc. from the Andrew Young textbook I need an additional condition added:

 - for buy orders OBV to be above its own Moving Average and

 - for sell orders OBV to be below its Moving Average.

Kind and period of the Moving Average to be applied by user in input section. 

Standard files from the MQL Book and standard OBV class from Metatrader 5 to be used (I will provide them).

The outcome of this order will be my .mq5 file (and other filies if need be) modified and returned.