How are Seasonal Base Prices Set?

I want to set summer pricing to be higher than winter pricing, and I want that reflected in my base price. I’ve done it manually so far, but the help center talks about a section called “long term pricing” that I can’t find. Anyone know how to do this? The help center page is:

I think that is no longer there… I don’t have “Long Term Pricing” anywhere that I can find.

That’s what I was thinking too. Thanks