If you have a mobile phone which looks something like this you are going to be unscrewing some very tiny screw before you can fix it. They are almost impossible to pick up (at least with my ancient arthritic fingers, and likewise to find when you (certainly) drop them – so you need to know how to do this. And it is just as simple as the picture shows. Wrap a length of insulated wire around the screwdriver then touch the ends a couple of times to opposite poles of a 12 volt battery (possibly not one installed in pone of these modern computerised cars which may not like it). You just have to run a current through the coil for a little while and the metal tip of the screwdriver will become magnetised and will remains so – often for a very long time depending on the steel alloy it is made from. That done you are ready to tackle those tiny screws.
I had not attempted a mobile phone repair before – I only graduated to a smart phone a bit over a year ago when I discovered its wonderful mapping/GPS functions – but I will have a go at petty much anything, and I succeeded first time in replacing the LCD & screen. Next time I will have a go at ungluing the glass screen with a heat gun and replacing it (very carefully). The screens only cost about $2 on the net so it is a knack worth mastering.
PS: A tempered glass screen protector will apparently prevent many such screen mishaps. They too are only about $2 on eBay!