Advice on cleaning and checking my Nautilus FNS DE filter

As soon as I can carve out some time I'm going to clean and inspect my filter. The pool water has slowly come around but still lots of cloudiness. Knowing it's moved a lot of algae through it I think a cleaning is in order. That, and when I've added DE to the vacuum hose (old pool has no skimmers) I've seen DE coming back into pool via returns.
I've downloaded the manual for my filter but thought it'd be good to ask out here for advice on the filter cleaning. Some 'watch out for...' and 'don't forget to...' would be invaluable. I've done some searching on the site but not fou d any threads specifically for "how to" info.

I'm not the DE expert but if DE is coming back into the pool when you add new DE, it might mean your screens are damaged or they are clogged need a proper acid wash.

I got some good info here including a link to a great site with step by step instructions for many DE filters. Ends up I had extremely dirty/clogged grids and cracks in my manifold. I replaced all of those last weekend and all seems to be running like a top now. And the water has cleared very quickly. I'm kicking myself (and cursing the pool company I paid to help open this year - it's my first time and I didn't know about this site) for not looking into the filter as a contributor to the slowness of getting water clear.