1) Go to https://bridge.xdaichain.com/. Connect your web3 wallet (MetaMask, Nifty Wallet) to the xDai Chain. Once connected, you will see your address populated in the header, and your xDai and Dai balance displayed on the page.
Note: If you change the dropdown on the page (xDai Chain) but not in MetaMask, the interface will shift but your wallet will not auto-connect to the chain. Switching chains in MM will automatically shift the interface.
2) Enter the amount of xDai you would like to transfer to Dai, and click the Request button. Note the minimum amount is 10 xDai.
3) Confirm that you will need to perform 2 transactions, and will need xDai and Eth to complete the transfer.
4) The web3 wallet window will open with transaction details. Click Confirm to process the transaction on xDai.
5) Wait for 8 block confirmations. You will see several popups with block confirmation info.
6) You will see a modal instructing you switch networks in your MetaMask (or other web3) to the Ethereum Network.
7) After you switch networks the Claim button will appear. Press to proceed.
8) Confirm the second claim transaction in MetaMask (you will need some Eth for gas fees). Once processed, the Dai should be available in your wallet.