The NS-RC4NA-16 remote was included with a number of different Insignia TV models. The suffixes for the compatible TVs are available here: https://www.insigniaproducts.com/pdp/NS-RC4NA-16/9974105
. Insignia TV/DVD models with those suffixes are not compatible with the NS-RC4NA-16. A quick setup guide is available on the remote product page when you click on the Support & Downloads tab. The current link to this guide is https://files.bbystatic.com/EwxdCPik%2Fmi66olq9%2BGq6A%3D%3D/NS-RC4NA-16_14-1146_QSG_V1_ENG_FR_SP_Final_lr.pdf .
For more information on using the remote with your electronics, you might want to check the manual for a compatible television. One such TV is the NS-55D420NA16. That TV's support page is here: https://www.insigniaproducts.com/pdp/NS-55D420NA16/9003104
. The user manual for the TV is https://files.bbystatic.com/g9A76XeZ%2FqQsD64zxUp5Fw%3D%3D/NS-55D420NA16_Manual_EN.pdf . Note: the NS-RC4NA-16 is not a universal remote and can't be programmed to work with other electronics.
If you wish to program a universal remote to take over some of the functions of the NS-RC4NA-16, you can find a list of possible codes in the online guide for the TV or at http://www.insigniaproducts.com/remotecodes
. To view the list on the TV, press Menu. Use the Left/Right arrows to navigate to Help. Press the Down arrow or Enter. Use the Up/Down arrows to navigate to Learn More. Press Enter. Again use the Up/Down arrows and go to "Remote Control Codes". Press Enter to see the list. Press Menu to go up in the menu system. Press Exit to leave the menus. At least on the NS-55D420NA16, you can do this navigation with the keys on the right side of the TV. Input becomes Enter. Volume +/- are the left/right arrows. The Channel Up/Down arrows are the Up/Down arrows. Menu is the topmost button.
I hope this helps. If you want to replace the NS-RC4NA-16, I've found it listed as available at Amazon.