Changing arco to pizzicato? (OTHER POSTS DIDN'T WORK)

Okay, many have asked this, but I still can't get it right. In order to change your instrument from arco to pizzicato in the middle of a song, you have to make a tekst and go to text properties. Then you have to click on "change instrument" but after that is for me still unclear. I can't select any instrument. There is no such a thing as "channel". Only ways to change the font, size and style of my text. HEEEEELLLP!