To Insert a Sheet Set Placeholder Field

Click Drafting tab > Block panel > Define Attribute.
In the Attribute Definition dialog box, under Advanced Options > Attribute Options, click Preset. Specify any text options.
Under Attribute, in the Tag box, enter a name for the attribute.
To the right of the Default box, click the Insert Field button.
In the Insert Field dialog box, select SheetSet.
In the list, select SheetSetPlaceholder.
In Placeholder Type, select the type of field that you want.
The Preview value previews the placeholder field.
In Format, select a capitalization style for the placeholder field.
When the field is updated, the same style is used for the value of the field.
Click Choose to exit the Insert Field dialog box.
The placeholder field displays its name when the Insert Field dialog box closes: for example, SheetNumber. Later, when the block is inserted, the field displays a value based on the sheet it is placed in.
Click OK in the Attribute Definition dialog box. Specify the location for the field text to appear near the geometry that you have created to use with the Sheet Set Manager as a callout block or a label block.
Create a block that includes the newly created attribute object along with the geometry for the block.