After adding SEO keyword tracking, you can expect your ranking data to update once per day. Be aware that every account's update schedule is different, so there is no specific time that this takes place.
To easily check if there is an update, navigate to the calendar widget in the top-right corner. If your SEO rankings are up-to-date, you should be able to select "Today" from the pre-defined periods as pictured below.
If you are unable to select "Today," check back later for updated rankings.