I need my sprite to stay on a ledge when he jumps onto that ledge and to fall when he isn't on the ground or ledge…. How do I do this?

Yvelocityne way of doing it is this.
“Forever change y by variable yv”

“If touching color ‘color of ledge’ than set yv to 1, else change yv by -.4”
“If touching color ‘color of ledge’ and up button pressed then change yv by 10”
Tell me if it works!

put this inside the sprite.

when green flag clicked
forever
    
repeat until <color [#f0f] is touching [#0f0]?>
change y by (-4)
    
end
end

when [up arrow v] key pressed
if <touching color [#f0f]?> then
repeat (10)
change y by (10)
    
end
    
end

There is some codding.

if <(Need help?) = [true]> then
    
ask [for help!] and wait
end

Thanks