how to set text in UMG to show only when my stamina is less than 15?

i just start and i am already have stamina system for my character and show current stamina in hud

but when my stamina is less than 15 i want to set text for warning on my character screen
and hidden that text agian when my stamina is more than 15
this is screen shot of my hud blueprint

please someone i cant find the way to do it by myself
please help me