First, add BNB to your wallet following theses steps:
2. Download Metamask (click here)
Next go to Roto Swap and enter the amount of BNB you would like to use for purchasing $ROTO.
Select a minimum slippage tolerance of 12% (set by default, if transaction fails you can try with a higher slippage).
Click «Confirm Swap».
You are now rotomooner. Welcome to the family!