GE Bottom Freezer Ice Build-up & Leak

Back from vacation and water on the floor - just what I was looking forward to. There was a layer of ice on the bottom of the freezer - and also ice build up along the top of the door (I noticed this a while ago and I shouldn’t have ignored it…) and kind of in where the ice cube trays go. I have done some quick research and looks like a clogged defrost drain is the first thing to look at. I’m having a hard time finding information on exactly where the drain is located on this model. One person (who had a similar model) said he called a technician and it took over an hour to repair - involved removing freezer door and disassembling the back, etc. I’m fairly handy - and unclogging something seems pretty straightforward - but if it involves a lot of disassembly to get to it, I would consider calling in a pro.

Can anyone provide information on how this is done for this model? Is it quite difficult?

Also - if I keep the ice cleared, do I buy time until repair?

There is no ice maker.

Thanks!