The quickest way to get to the section where you can enter your SEP IRA contributions is to type "self-employed retirement" in the Search box (upper right of your screen) and then click on the "Jump to self-employed retirement" link.
I'm lost. All the answers to this and similar question mention a "Jump To" link in the search results. I'm on the online version and get no such link. @Rachel_W are you on the online version and does this still appear for you? I'm thinking maybe the answers are all out of date.