Remote Starter Instructions I Have A Valet Remote Starter On The Used Car I Bought But The Keyless Entry Apparently Wasn't Installed...

I have a Valet remote starter on the used car I bought but the keyless entry apparently wasn't installed... - remote starter instructions

Is this something I can do, and if so, where can I get instructions? (I have the manual), it took me a store and was told it would cost to about 60-80 that was created because I needed parts, but I do not know whether or not correct. Any help would be appreciated.