Your screenshots are from the Family Editor (ie you are editing an .RFA file), showing the Family Types page. You would load this Family into a Project (.RVT file) (using the 'Load into Project' button), before creating an Instance of your Window by using the Add Window tool and selecting an existing Wall object as a Host. Objects such as Windows and Doors require a Host object.
Families can each contain one or more Types, depending on how you define them. In your case, your have 3 options for the Panels (1,2 & 3) but only 1 actual Type defined (because the 'Type' field at the top of the page is blank). This may or may not be desirable to you. You can edit / create / delete Types, as well as the 'Panel' Parameters. The Parameters can apply either to a Type of an Instance. To edit a Parameter, highlight it and click the little 'pencil' icon on the bottom left of the Family Types page. In your case, they are most likely set to "Instance" (because there are no Types defined).
The checkboxes control a Visibility parameter, either On or Off. If you select a part of your Model, there will be a 'Visibility' setting on the Properties palette. You can set this to On, Off or else select one of your Type Parameters. It looks like this has already been done for this Family, so all customisable components will have a Visibility setting mapped to one of the existing Type parameters.
Once you've loaded the Window into your Project, and created an Instance of it, you can then put ticks in any of the Checkboxes and see the results.
Because the Parameters are (probably) Instance Parameters, the checkboxes will appear in the Properties list whenever you select your Window. If they don't appear, then click 'Edit Type' near the top of the Palette.
If you create new 'Types' in the Family editor (ie Type 1, Type 2, Type 3) and change the Parameters from 'Instance' to 'Type' then you will be able to pre-select the Panel parameters to suit each Type. This is more structured and generally better practice. Then when you select you Window from within your Project, the Type will show up above the Properties palette which can be pulled down to select a different Type. You can create and delete Types in either the Family Editor or from within your Project itself.
Good luck. When you are editing Parameters, you also might want to change the 'Group parameter under' setting to something other than 'Dimension'. This won't change anything but looks better.
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