RPCS3 for Newcomers

For decrypting them, you need to rename the module to modulename.sprx.elf, and then use the "Boot ELF/SELF file" option on RPCS3 under "Boot".
The emulator will fail to run it, but you'll have decrypted the module.

I have the original module and its decrypted version. Do I delete the original and rename the decrypted or ???

for reference my external folder houses:

1234.sprx.elf
1234.sprx.elf.decrypted.elf

You can have them both decrypted and encrypted in the folder, but it will only detect and load into the LLE modules window the ones who are decrypted.
For the sake of organization, I keep the decrypted modules separated from the encrypted ones, and I only place the decrypted ones on RPCS3.