There are many options to change the sort order of emails in AltaMail.

When you are viewing an email folder, tap on the action menu. (circle with 3 dots button). Tap on Sort by to select a sort order. Select the same sort option again to reverse the sort order. An arrow will appear beside the selected sort option to show which direction it is being sorted by.

You can also add your own sort actions by tapping on the settings (cog) button in the top of the Sort by menu. In the Email Searches screen you can tap on the "+" button to add a new search and choose the sort fields that you want to use.

If you want a more advanced email folder layout such as grouping and filtering, then you can use Split Panels. (View)