No need to buy the FSM, it's available here, on-line for free. The fuel system is detailed here:
http://www.nicoclub.com/FSM/Altima/2008/fl.pdf(download all the sections and they are neatly linked together, too about 3 minutes to locate this info, VERY handy)
It appears most Japanese cars are moving to the in-tank fuel filter which is called "lifetime". I'm skeptical, but the one in my Accord seemingly lasted 238,000 miles. I miss the old, firewall mounted filters and used to replace mine annually. But my hands no longer smell like gasoline. Heck, even my '04 Chevy truck no longer has a replaceable fuel filter.