By default, Minecraft is set to the most current version of the game. However, there are times when you may want to change to another version, such as a weekly snapshot (beta version). The steps below will explain exactly what you need to do to play such a snapshot.
Open the Minecraft launcher and click Installations.
Enable snapshot versions by checking the snapshots checkbox.
Create a new version by clicking New.
You can now select a snapshot version. Use ‘latest snapshot’ to always use the most recent snapshot version, or select an individual weekly snapshot.
Hit Create to create your snapshot version. Before you do this, you might want to name your version so it’s easily recognizable.
Go back to the play menu and select your snapshot version from the version menu at the bottom of the page. In this case, I’ve chosen 1.14.4 pre-release 5. Then hit play to play using the chosen snapshot version.