I assume that the end you are talking about is the back end small hole rather than the front of the scope where the big piece of "window glass" is. If it was on the small hole, you have actually done something good by throwing the filter away as those kinds of filters are dangerous. If it was on the big end, the filter just needs to be placed on the aperture to be useful.
BTW, if that window ever breaks, a repair will be very expensive unless you make a new Schmidt Corrector plate yourself because that is what it is. It's not a flat piece of glass but rather one with some subtle curves in it. Do a search on the web for Schmidt Corrector and you will see what the glass is.