how to build a incubator from a Styrofoam Cooler ??

im new at this & my snake had 5 eggs 10 days ago.
we build a incubator out of styrofoam cooler, but im not sure it's right.
so to be safe i was wondering if ne'one could tell me step by step
how it should be put together.
im new to ballpythons.net & im not haveing much luck when i search here or on google for picture or directions.

this is what mine looks like now..
[it is working, the temp is 88-90 & hum is 80%]

http://i295.photobucket.com/albums/m...TURES/s002.jpg

& i just wanna make sur it's right or if theres improvements i can/need to make.
im not a breeder, i think she got pregnet before we got her & she was being housed with 2 males. but the past 8-9 months weve had her she's be alone. so we were in no way prepared for eggs. i've been reading ne'thing & everything but most of what i read gets contradicted by something else i read. so if nr'one can help me with the most simplest directions [apart from buying one] i would be very greatfull...