Tom Bricker from Disney tourist blog has a few posts on how to stack afternoon/evenjng LL. As the PP mentioned it just means you are booking return times in the afternoon instead of morning. So you use those morning hours and ride things standby, but book a LL later in the day, wait your 2 hrs, then book another.
It doesn’t always work out seamlessly, so I tend to book one LL in the am for a “must do” ride, and once I scan into that I will look for a later return time in our second park or in the evening if not park hopping. If a later time for the ride I want isn’t readily available I’ll either wait a bit to book, or choose another LL in the park I’m in if it has a close return, and lather rinse repeat.
On especially busy days the return times can get pretty late pretty early so it all depends on the day. I am firmly in the
Genie+ camp of “this is my fast pass for 3 rides, everything else is frosting” camp. So I tend to prioritize those top 3 rides and secure them with a LL, and then go about my day - if I score a few more, great. If not, no big. I am not about taking genie+ to the max cause that’s just not my touring style.
EDIT: although with G+ now starting at $25 I may be augmenting my approach.