Its ok I know what will have happen as I see it a lot on these.
What you need to do is open the main oven door a little.
On the top you will see a screw either side.
Hold the handle and remove both screws and then you can lift the door glass out from there.
Now you will see there should ne 2 plastic brackets sealed to the door glass in the bottom corner. They will have come away.
You need to get some high temperature sealent and reseal the brackets back onto the glass in the correct place.
Leave it a few hours to dry.
Once dry you can then locate the brackets into the bottom of the door frame and refit the glass back to the top and refit the screws.
Once the door is off you will see how the brackets go. But it has to be high temperature seleant you use on the door glass otherwise it will come off again sooner rather then later.
Try the above and that should cure it from there. If you need anymore info just get back to me.