Shift the chain onto the smallest rear cog and smallest front chainring
Inspect the chain for a broken link, bent link, rust, or severe wear
If the chain is broken, use a chain tool to remove the damaged link
If needed, install a new quick link or reconnect the chain with a chain pin
Check that the chain length is correct and shorten or replace it if necessary
Clean the chain and drivetrain if dirt or rust is causing poor movement
Lubricate the chain after cleaning
Reinstall the chain on the chainrings and cogs
Pedal backward by hand to check smooth movement
Test shifting through all gears
Replace the chain if it is too worn, stretched, or repeatedly fails