@bjac0 alright cool thanks

Step 1
Go to your steam library and go to SimplePlanes
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Step 2
To the right of the "Play" button, play time, etc. There should be a cog button labelled "manage" when you hover your mouse over it. Click it, then click "properties"
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Step 3
Under "Betas" there should be a prompt where you select what beta to opt into. Select "public-test"
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Step 4
Wait for the beta to download and have fun screwing around with the new features!