Notice For New Users: Manually Update HandbrakeCLI.exe if you plan to use your existing Handbrake Preset.

[ShikuTeshi]

Since HBBatchBeast works but doesn't appear to be updated with every latest release of HandbrakeCLI and FFMPEG as they come along. Updating those yourself is pretty mandatory and not complicated. Though it would've been nice to see HBBatchBeast get a built in update/downloader from the respective githubs before it ceased updating.

If you plan on using a Handbrake preset over ffmpeg parameters in HBBatchBeast then you need to make sure you manually update the necessary exe file.
https://handbrake.fr/downloads2.php
Simple drag and drop replacement works.
This will make sure the latest Handbrake parameters will work. Especially HEVC/x265 encoding.

Then to actually use a Custom Handbrake preset you made, simply right click it in Handbrake and export to file.
Then fill in the following in the Custom Preset box within HBBatchBeast.
--preset-import-file "C:\Users\HaveAGitGat\Desktop\testpreset.json" -Z "My Preset"

And I suppose the same can be said with ffmpeg if you run into issues with it not working. Just make sure your parameters are working with the latest version of ffmpeg before you use that latest version to update HBBatchBeast to make sure you're not using deprecated commands.