First, navigate to the SAFE or convertible note you would like to convert. Select "Actions" in the top right and choose "Convert convertible."
Next, select the certificate that the SAFE or convertible notes will convert into. This will be the Preferred Stock certificate held by the issuer of the SAFE or convertible note after you raise a priced round.
For convertible notes and SAFEs, input the amount outstanding on the agreement in the "Debt Cancelled" box.
Add the cancellation date, which should match the date that Preferred Stock was issued to the issuer of the SAFE or convertible note - in other words, the closing date of your priced round.
Finally, select the applicable "Cancellation Reason" and hit "Next".
Select "Convert SAFE" on the following screen and your cap table will be updated to reflect the conversion.
Learn more about SAFE conversion here.