There's actually no action needed on your part here :)
Since Digit is connected to your bank account, it's working with your bank to identify it's own transaction into your account to verify that we're pointing to the right spot. This process can take a few business days to complete in rare cases, but most of the time it's pretty quick.
You should be all good moving forward hopefully and Digit will confirm when it's ready to start saving. If, of course, you don't see Digit start automatically saving for you soon, please let us know and we'll be happy to help dig in further for you!