For this example create two fields in the repository to be used as the basis of the columns in the property sheet: #PROPERTY and #VALUE. Make the reference field for both of them #STD_TEXT.
In the editor, drag these fields from the repository to the property sheet to create a column for the property descriptions and another column for the property values. (As a rule a property sheet should always have two visible columns. In some cases you may want to add other columns which are not visible.)
Note that in a property sheet you do not want the columns to be based on fields with data as you usually do with lists. This is because every row of the property sheet will display a different attribute based on a different field. When you add columns all you are doing is defining the basic structure of the property sheet.
Make the Width of the first column 50 (WidthType Scaleable) and the WidthType of the second column Remainder.
The first column which contains the description of the properties should always be based on an alphanumeric field. The second column should usually also be based on an alphanumeric field (to show the values as strings) except in those rare cases where all entries in the property sheet take numeric values.