Typically adjusting the front derailleur is a matter of adjusting the two adjusting screws on the derailleur. So turn the bike upside down. It should sit on its seat and handle bars. Find the two adjusting screws one will prevent the derailleur from traveling too far out preventing the chain from coming off. The other screw prevents the derailleur from traveling too far in keeping the chain from falling off that way. Now once you have found the screws slowly start turning the pedals like it was being ridden. Move the derailleur out as far as it will go if you see the chain is about to come off adjust the screw. Do same for inside screw. Now move the back derailleur all the way in and retest front derailleur, repeater with rear derailleur all the was out. Hope that helps. Oh, the back derailleur adjusts same way.
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Typically adjusting the front derailleur is a matter of adjusting the two adjusting screws on the derailleur. So turn the bike upside down. It should sit on its seat and handle bars. Find the two adjusting screws one will prevent the derailleur from traveling too far out preventing the chain from coming off. The other screw prevents the derailleur from traveling too far in keeping the chain from falling off that way. Now once you have found the screws slowly start turning the pedals like it was being ridden. Move the derailleur out as far as it will go if you see the chain is about to come off adjust the screw. Do same for inside screw. Now move the back derailleur all the way in and retest front derailleur, repeater with rear derailleur all the was out. Hope that helps. Oh, the back derailleur adjusts same way.