It sounds like it is important that Autumn is ok with going in the basement. Have clicker trained her at all? If you have I would start off with a click for simply looking at the basement steps. Do that for a few sessions ( 5 min ) a few times a day for a few days, then click for looking at a steps and one step(she walks one step forward) towards the steps do that for a few days. When she is ok with that then click her for standing on the first step. Do this for a few days. When she is ok with that then move to the next step click, etc. This will be a very slow process, but it will work. When you are training this use really good treats, cut up chicken, steak something of very high value. If you find her not wanting to do one of the steps then you are moving to fast go backwards just a little.
It would be best if she does not have access to the stairs if you are not actively working with her, that way she won't look at the steps and not get rewarded for it. Good luck.