Alphabetical order is A, B, C... X, Y, Z. You can save wanted mail messages in a folder and sort that folder. e.g. Sort by "From" and the Sort order "Ascending" and that will show messages in A - Z order using the friendly From name as the sort operator.
A message from Ady will appear in the sorted list before Chris and Chris will appear before Debbie.
You're asking how to locate these saved emails. I don't know where you saved those emails. TalkTalk Mail has a powerful Search function and you can use that to search for messages by From, To, Subject, Contains words, By Date or Date range or a combination of the above and more.
Let me know if you are in need of further guidance.
