This article explains how to create day-ahead comfort bids

Navigate via the top menu to "Auctions." Here you'll find a blue button which says "New day-ahead comfort bids" (shown in the bottom right of the image above). 

When you've clicked on the button, you'll come to this view, where you have to select a network point to proceed. 

Specify information about the capacity and submission interval. The submission interval is the time, in which the comfort bid is active and places bids for you in DA auctions.

Once this is done, options for specifying your bid(s) will appear. Enter the desired values and check the check box for roll over (if desired), then proceed.  The rollover functionality means that if you do not receive any capacity in the day-ahead auction (due to high demand for example), your specified bid will be placed again in the first within-day auction at 19:00 that day (which has the same runtime as the day-ahead auction).

Before you accept the GTCs you can check that all the information you entered is correct on the "Confirmation" page. 

After clicking on "Save & Submit", you'll be taken to the overview. Here you can see your existing comfort bid(s). You can also start a new comfort bid with the button at the bottom right.