Duplicate the Drum-snare sprite:

Click on the Drum Costumes sprite and select the Costumes tab.

Choose: which drum to unlock next. We chose Conga.

Drag the 'hit' and 'not hit' costumes of your chosen drum to your new Drum-snare2 sprite:

Name the new drum to match the costumes you chose.

Click on the Code tab. Change the code to use the correct costumes and choose a sound for your new drum.

Change the number of beats you earn by clicking the new drum to 5:

when this sprite clicked
+change [beats v] by [5] //5 beats per click
+switch costume to [ v] //your hit costume
+play drum [ v] for [0.25] beats //your drum sound
+switch costume to [ v] //your not hit costume

Drag your new drum into position on the Stage:

Duplicate the Get snare sprite and position it in the bottom-right corner of the Stage.

Change its name (for example Get conga):

Delete the snare drum from the new 'Get' button costume.

Copy the 'not hit' costume for your new drum and paste it to the new 'Get' button costume.

Click on the Text tool and change the number to 30 to show the cost of the new drum.

when flag clicked
+ hide

Add a when I receive script that your new 'Get' button will show when the player unlocks the snare drum.

when I receive [snare v] // appear when previous drum is unlocked
show // show button to get the new drum

Change:

• The number of beats needed to unlock this drum
• The number of beats that are removed when the player unlocks this drum.
• The message that is broadcast when the player gets the new drum.

when this sprite clicked
if <(beats)>  [29]> then // change to 29
hide
change [beats v] by [-30] // change to -30
broadcast (conga v) // change to your drum name
else
say [More beats needed!] for [2] seconds 
end

Click your new drum sprite and change the when I receive snare script to show it when your new drum is unlocked:

when I receive [conga v] // change to your drum name
show

Add the Party backdrop.

Add a script to the Stage to switch the backdrop when the player upgrades to the new drum:

when I receive [conga v] // change to your drum name
switch backdrop to (Party v)

Test: Click the green flag to start the game.

You should unlock your new drum if you earn enough beats.

What happens if you click the button before you have earned enough beats?