There are 2 ways to sort search results in REALM.
Choose an option from the Sort Menu:
In any Layout view, click the Sort button to choose from a pre-defined list of Sorting options.
To sort by options not included in the Sort Menu:
In any Table Layout, click on the Columns Drop down and choose Customize
Towards the end of the window is a section called Multi-Level Sort. Enter your desired Column name into the Add a Column field.
Each time an item is chosen in "Sort By", a new line will appear to choose other sort levels.