First, you must have already started to enter your Schedule C (business) data.
Second, you can enter "sep ira contributions" in the Search filed on the upper right. The first search result should be "jump to sep ira contributions". Click on the result and you will go directly to the first input screen for the SEP IRA.
Or you can navigate to the "Let's Gather Your Business Info" screen. Look down the screen for the subheading "Less Common Business Situations" and click on Start or Update for "Self-employed Retirement".
These instructions work for the desktop version called Home & Business. I cannot guarantee that the Online product Self Employed is laid out the same way, but looking for the jump as well as looking for less common business situations would be worth the search.
