Hold the ukulele in playing position
Identify the strings from top to bottom as G, C, E, A
Use a tuner app, clip-on tuner, or pitch reference
Tune the G string to G4
Tune the C string to C4
Tune the E string to E4
Tune the A string to A4
Turn the tuning pegs slowly
Tighten the string to raise the pitch
Loosen the string to lower the pitch
Pluck each string again after adjusting
Recheck all strings after tuning
Repeat until each string matches the correct pitch
Tune again after the strings settle
Check tuning before playing each time