Essays / Creating an introduction and thesis - genetic engineering hazards essay [9]

Hi, I'm a little bit confused about how to start my essay.
I know there are already so many threads about this, but i just can't find one that fits my question.
what i wanna ask is where should i put the description of genetic engineering?
what should i write in the introduction? what kind of general information?
can anyone give me the right essay order? thanks =DD