You can't select its inputs without a remote control. If you wish to get more details; check the sites linked here. It has set-up code list & set-up procedure to many popular brand remote controls. Common codes to check devices with different brand TVs are given, in the order of the device's brand name list in alphabetical order. Pull up older posts. Surf the site with patience.
http://electro-medical.blogspot.com/
http://remotesearch.blogspot.com/
http://electrohelponline.blogspot.com/