Looks pretty good . Definitly check over the quad before you start riding it . Download the service manual for general info and specs on the quad . Ask questions on here if you need help .
I would start with:
Check the front end...tie rods...ball joints...a-arm bushings . Steering shaft bushings
Front wheel bearings and brakes
Swing arm bearings
Rear axle bearings and brakes .
Change the trans. oil
Check the condition of the reeds
Look at the sprockets and check the chain for proper tension and wear
New spark plug
Clean or get a new air filter
Check compresion to see how it is . Leak test the motor .
Torque the wheels to spec
Make sure clamps on the carb. are tight
I can go on and on lol