Hi,
Rubold is correct.
The best way to learn how to design your own trigger is put up a request, either public or private, with precise instructions of everything you need and someone will write it for you. Then you test and test the trigger, learning how it works, the sequences and the flow of the conditions etc etc.
Then, you save the trigger under a different title; go ahead and change some conditions or add another firing trigger etc etc and experiment in that way on many test markets, always keeping the original trigger unchanged for reference purposes. If you come across something specific that doesn't work as you think it should, then you use the search forum for similiar previously solved issued.
You will have many many queries in the first month or even two.