I will do my best to explain it here for you.
Checkboxes will contain the value of whatever you specify in the value attribute, but only if the box is checked. So if you have the value of the checkbox be 1 that form element will have a value of 1 if it is checked.
If the '1' is the value from the checkbox you can get it to say yes if update the value of the checkbox to be yes on the insert and update pages.
You can also make this change in the code directly using a ternary expression like this:
<?php echo ($row_YourRS['the column'] == '1')?'Yes':'No' ?>
This is equivalent to saying if the column from the recordset is equal to 1 then write yes, otherwise write no.
I edited this post to add in the part about showing the default value. To do this select the checkbox then in the properties panel click on the dynamic (lightning bolt) button. In here you can specify to have the box checked if a certain value is present.
If this is not enough info to help you get it worked out please post back and include some more details about how far you have gotten in these steps and what the result is. It may also be helpful to post back with the pages in a zip archive so that they can be examined.
