To adjust the front derailleur, you need to use a bungee cord to hang the bike. Make sure the pedals and wheels have space to rotate. To find the front derailleur, follow the cable from the left shift. Next, turn the pedals forward. If the chain does not move well, you can adjust it by turning the screw marked L. Next, shift the big chain link. You can adjust it from the screw marked H.
If necessary, fine-tune the adjustment. For bicycles with STI shifting, you need to fine-tune the cable tension. Check if the chain is on the small chain ring. In this case, the front cable must have a little extra space.
To locate the rear derailleur, go to the right shift lever and follow the cable. You can see two screws marked with L and H. Turn the pedals and loosen the H screw if the chain doesn't move as it should. The L limit is very important, because if it's not right, the wheels can collapse.