How to include deca device library in arduino

Wireless Connectivity Ultra-Wideband
1

I need deca_device_api.h as I need to use some struct like dwt_nlos_alldiag_t in my code. How do I add the library in Arduino.

2

There are DW1000 / 3000 libraries for arduino (e.g. makerfabs). These are generally just a wrapper around the decawave drivers so if you look inside those libraries you should find all the decawave files.