Sadly, I cant provide any screenshots, but what you have to do is go to your launcher, and in the middle, a bit to the higher half of the screen there should be a button called "installations". When you click that button it leads you to a new "page" and there you have to click the new button. Then you will select a version (My recommendation would be 1.14.2). Then you go to the play screen, bottom left click the arrow and click the installation that you just created (1.14.2)