Data Indexes: More detail?

Can someone help me find more detailed documentation on "Data Indexes"?

Primavera Unifier 9.13.9.1

In our continued effort to improve Unifier Performance for our end-users, it's come to my attention that "Data Indexes" in the "Data Structure Setup" could help.

I've created several indexes, and I have a vague sense that it may help performance in other areas as well.

Despite my best efforts, I haven't been able to find detailed documentation on what these indexes do, how other searches may be able to make use of these indexes, whether/how they stay up to date, and some tips on how best to select fields for indexing. I'd also like to be able to point to specific areas where the indexes are helping.