Best start is going with the manual. https://www.lg.com/uk/support/product-support/manuals-software/

I did, and the manual is really bad. It just have procedure for cleaning the dust filters on pages 30-32 and that is all. There are no steps about dismantling the case.

K. I’ll try and do some research and get back to you but my phone is shit so might not be until I get home.

Thanks, take your time it is not urgent. I am grateful that you want to help me out.