Stackable Lightroom presets can be used together and enable photographers to edit photos with flexibility and speed. These presets are designed as a editing workflow and you could pick at most one preset from each category, where the presets from the same category will be indicated with the same item number.

A typical workflow will be like this:

1. Apply a colour preset (1. Karuizawa - Base)
2. Apply a highlights tool preset (2b. Highlights Soft)
3. Apply a shadows tool preset (3b. Shadows Soft)
4. Apply a film grain tool preset (4a. Film Grain (Mild))

Picking more than one preset from the same category will overwrite the previous edits. For example, if you apply 3a. Shadows Hard and then 3b. Shadows Soft to a picture, the preset 3b will overwrite the edits done by 3a.

Please follow official instructions from Adobe which can be accessed with the link below.

https://helpx.adobe.com/lightroom-cc/kb/faq-install-presets-profiles.html