Installation

Open your blender and follow the instructions in the image

Click on the install button and then select the add-on and click Install Add-on

How to use:

Go to the render tab

Scroll down and find the "Render Preset Manager" option

First, click on the folder icon next to the Preset folder input, and select an empty folder, this is where your presets will be saved as a JSON file.

First make your changes, then click the plus(+) Icon to create a new preset, It will ask you to give a name and select if you want to save render and output tabs options with checkboxes (i.e. selecting all will save every entry from both sections, even the defaults)

Or Click the cog wheel icon to modify existing presets

And that's it! Click refresh if the list doesn't update, it should show your preset names. Now you can click and select on the preset and click Load selected preset to load your preferred preset, These presets will be loaded on any blend file you open and after you select the same preset folder.