i'm only given the tank height for a project.how can i find the number of courses should be used and their heights? thanx a lot

You'll more information than that. For instance, can you purchase plates 6ft wide or 8ft wide? Another factor to consider is the cost of fabrication - more courses mean more welding.

thank you for your answer, i also wonder about the difference between course height and tank height?

The course heights must add up to the overall tank height.

hi there,
i know required tank volume,height and diameter.how can i find average course height,max/min tank heights and also max/min tank dia.
thank you

There are some guidelines in "AboveGround Storeage Tanks" by G. Myers. There are a whole lot of variables that come into play here, things like available real estate, obstructions and so on. I can't tell you how to do this in this forum or via e-mail. You should find someone local who has done this before and have them walk you through it.