A G chord is a G chord in the air. On the neck it is a shape. Guitar and ukulele use different tunings, so the same name draws a different picture.
Each song page prints both. Guitar, ukulele, and piano sit in one fingering block. You do not have to leave the chart to see how a C looks on four strings versus six.
The pad still plays the sounding chord. The diagram is for your left hand. If you only tap the pad, you can ignore the dots. If you hold a real instrument, the dots are the map.
Standard guitar is E A D G B E. Re-entrant ukulele is G C E A, with a high G on many sopranos. A C shape that is open and easy on uke can be a stretch on guitar.
Barre chords are a guitar habit. A ukulele player can often stay on open shapes longer because the scale is short. That is a size fact, not a virtue contest.
Piano has no capo and no barre. The same page shows white-key clusters for the same names. Use that view if the neck picture is still noise.
Open Amazing Grace and switch your eye from guitar to ukulele on the same G, C, and D. Notice which shape uses open strings. Those are the ones that ring if you are still building grip.
Ode to Joy and Are You Sleeping keep the letter count low, so you can compare instruments without also hunting a rare chord.
Silent Night is slow enough that you can form a shape, look at the diagram, and still catch the next bar.
G major and C major are common first keys on both instruments. D major loves guitar. F major is easier on uke than on guitar for many beginners.
If a guitar page is full of barres, move the key chip toward G or D and see if open shapes return. The melody may sit differently in your voice. That trade is yours.
Three-chord Song and The Four Chords are useful drills. Loop four shapes and look at the diagrams. There is no lyric to chase.
The chord player online opens the Songbook. Pick a page, set the instrument in the player, and keep the other diagram visible so the two necks stay honest.