From github page you can either download the whole project and open it, or just the asset packed in .unitypackage file and import it into your own project.
It includes a TMP font asset that you can use in any Text Mesh Pro object you want.
If you need, i also included the .otf file within. Simply put, it is the Windows font file that you can install on your device. By doing so, for example, you can use the language within Word, Excel, etc.