Welcome to QUADCRAZY! In the downloads sections there is only a newer LT50 manual and you'll have to search online for an older version I think.
As far as finding part, fenders, seats and such for an older model ATV, start with ebay.com where you'll find some new and used fenders for Suzuki LT50 ATVs
You can also check Amazon where they have front and rear in yellow and white, similar priced to new on ebay
Maier USA Suzuki LT50 QuadRunner Front Fender - Yellow - 177884
Maier USA Suzuki LT50 QuadRunner Rear Fender - Yellow - 177894
Same with your other parts, look on ebay and then check amazon because you'll usually find a good price this route. Then start checking the mainstream ATV websites like motosport, rockymountainatv, bikebandit, etc.,