1)Set up ADB on your computer.
2) Enable USB Debugging on your phone.
3) Connect the phone to the computer.
4)Open command prompt and use the command "adb logcat"
But You might not fully understand what is written there. You need to have some Android knowledge in order to understand them because of course it's not just written in normal human English :P like your phone is not gonna tell you "I'm not working because of this app"
haha anyway , Good Luck figuring out what crashes your phone.