Gather a frame, fork, handlebars, stem, headset, wheels, tires, tubes, drivetrain, brakes, saddle, seatpost, pedals, cables, and tools
Install the headset into the frame
Attach the fork to the frame through the headset
Mount the stem and handlebars
Install the seatpost and saddle
Attach the front and rear wheels
Install the bottom bracket, crankset, chainrings, and pedals
Mount the front and rear derailleurs if needed
Install the shifters and run the cables or housing
Install the brake calipers or disc brakes
Fit the tires and tubes onto the rims
Inflate the tires to the correct pressure
Install the chain and adjust drivetrain tension
Adjust the brakes
Adjust the gears
Check all bolts for proper tightness
Test the bike for smooth steering, braking, and shifting
Make final safety checks before riding