From the file menu, select Manage | Value lists...
Enter a name for your value list and type the numbers into the custom values box, pressing return after entering each value.
Click OK twice to dismiss the dialog boxes.
Enter Layout mode and place a text field on your layout. Drag the selection handles so that the field is large enough to show all 23 check boxes. If you don't get the size just right, you can adjust the size later.
While holding down control (windows) or Option (mac) click and drag on this field to one side to make a second copy of the field--this isn't required, but I want to use it to show you how check boxes work. Place the two fields side by side.
Double click one of these fields to bring up field/control | Setup
Select check box set from the Display As drop down.
Select your new value list from the Display Values From drop down.
Click OK to dismiss the dialog
If you can't see all the check boxes in your field, click on it and change the field's size until all are visible.
Enter browse mode
Click on different check boxes and notice what appears in the second copy of the field.
The unformatted copy of the field shows you what is really being stored in the field as you check and uncheck checkboxes.
That clear things up?
Alas, that didn't help. The check boxes are all there. However, when you are entering a record and you click in any of the boxes, nothing happens.
Check the field.
Is it a text field?
Is it a field that is part of the current layout's specified table?
Actually it can be a number field and still work correctly. I was thinking that if you set up a number field with check boxes, the unformatted copy of the field might not correctly display the carriage return separated list of values and that might explain the problem, but my own little test did not show that.
Scratch the idea that the check boxes weren't showing as "checked" due to the field in question being of type "number".
I'd try the original steps I described on a brand new file and see if it works then. I suspect something in the original file is interfering in some way.
You are arguing with a spam bot...
I know and reported the forum name as such, but still chose to respond in order to correct a mistaken idea in my earlier post.