I gave the whole micro-SD card storage for the OS via "7 Advanced Options" > A1 Expand File System".
Using 1024 result in a black screen after reboot) Give at least 512MB or more to your GPU via "7 Advanced Options" > "Memory Split" (I did set 512.Enable SSH via "5 Interfacing Options" > "P2 SSH".
#PLEX MEDIA PLAYER 32 BIT INSTALL#
Once the operation completed, install the micro-SD in your RPI 4 and turn it on.img file "YYYY-MM-DD-raspios-buster-armhf.img" unzipped from the "Raspberry Pi OS (32-bit) with desktop" image. Install and Run the "Raspberry Pi Imager" to setup the "Raspberry Pi OS" on a micro-SD card.This is the smallest image (no extra softwares) with a Desktop (mandatory to display the Plex Media Player GUI).Download next the "Raspberry Pi OS (32-bit) with desktop" here (the 64-bit is still only in beta.Download the "Raspberry Pi Imager" here.