In Search and Options group in the ribbon you will find features which may help you organize issues you have got in the sheet.
Searching
In search text box type in phrase you would like to find. Rows which do not contain the phrase will be hidden.
Sorting
You can put your issues in alphabetic order by clicking on the column you would like to sort your issues by and then clicking one of the buttons with Sort label.
Sorting may cause your subtasks to be put far from parent tasks. In order to prevent that just check Preserve grouping while sorting checkbox and your subtasks will stick to their parents after sorting.
Managing columns
If you want to hide some of the columns, you can use the Manage columns button. You can also move selected column to the left or the right by clicking suitable button with Re-order column label.