Breakdown Sheet - Scene ID

If you want to add the episode ID to all or many scenes in a script, use Set Episodic Prefix in Scene Tools (Story Order window).
If you want to renumber all or many scenes in a script, after making changes, use Renumber Scenes in Scene Tools (Story Order window).

Add /Change Episode ID (prefix), Scene Number, Scene Part ID (suffix)
Click on ID button OR double-click in scene number/ID in Breakdown Sheet;

Click in and Type in Prefix, Scene ID and/or Suffix;
Return OR Click on Apply.

Add Episode ID (prefix) to many/all scenes in script
Open Strips Window (option-command-W);
Click on Story Order(1);
Click on the first scene for the Episode ID;
Shift-click (or command-A for all scenes) on the last scene;
Click on Scene Tools(2).

Click on Set Episodic prefix…

Type in the Episodic prefix;
Return OR Click on Apply.

Clear Episode ID (prefix) from many/all scenes in script
Open Strips Window (option-command-W);
Click on Story Order;
Click on the first scene for the Episode ID;
Shift-click (or command-A for all scenes) on the last scene;
Click on Scene Tools.
Click on Set Episodic prefix…
Click on Clear.

Renumber scenes
Open Strips Window (option-command-W);
Click on Story Order(1);
Click on the first scene for renumbering;
Click on Scene Tools(2).

Click on Renumber Scenes

Click on Auto number (numbers each scene to the end);
OR Click on Apply (numbers a scene at a time);
Click on >> to go to next scene;
Click on Cancel to finish.
Note: auto number will stop at each scene with a suffix.