I just upgraded my Dell Inspiron 7620 Plus laptop from 16GB DDR5 4800MHz to 64GB DDR5 5200MHz. You can follow the video in the link below for the upgrade.

Note that after installing the RAM, you will have to wait for 3-5minutes after powering up before the Dell logo appears on the LCD and the system will boot into the bios and warn you about memory change.

For a moment it would seems that your laptop is dead when nothing shows up on the screen when you power up. Do wait for a few minutes for the screen to load.