pls anyone cud giv me any references about how to make a step-down transformer having output of 30volts and 6 amperes

 

Making power transformers is not generally a task that a novice should attempt. I'm an old retired engineer, and I wouldn't try it.
Having said that, before anyone could help you, they would need to at least know the input voltage and frequency.
EDIT: I just realized that you posted this under Homework, so my first comments are probably not relevant.

 

I just googled "transformer winding tutorial" and got some interesting results.
Everything from basic transformer theory to to some pretty complex design info.
Please post again with specifics of your project if you need more help.