To write a system test, you must first answer several questions:

1) Will this system do only Long positions, only Short positions, or Both?

2) What events will trigger the trade entry and exit signals ?

3) Will this system all more than one trade to be active at once? If so, can both Long and short positions be open at the same time?

Other questions may arise as the system in being written, but these are a good place to start.

After you have your answers to these questions, formulas have to be written to discribe the signal you chose. It sometimes helps to write the signal formulas as custom indicators so you can see on a chart where the signals will occur.

Once the signal formulas are correct, you are ready to create the system test:

1 - In MetaStock, go to Tools -> Enhanced System Tester
2 - Click New
3 - on the General tab, enter a name for the system
4 - if the system will allow multiple trades to be active at once, set the maximum number of trades at the bottom of the General tab
5 - if the system will allow both long and short trades to be active at the same time, set the portfolio bias to multiple.
6 - on the next four tabs, enter the Entry and Exit signal formulas you already created. If the system will only trade Longs, or only trade Shorts, you only have two formulas to enter, otherwise, you will be entering four.
7 - click ok to close the system editor.

some systems may require the use of some of the other settings, but the above steps are generally all that is required.