It should have come with a USB connector to that lets it "talk" with the keyboard and mouse. That needs to be plugged-in and you might also need to install the software drivers for it with the cd/dvd that it came with.
If you don't have the cd/dvd, you can look up the model number and download the drivers from the manufacturer's website.
Give us a little info. to go on. What manufacturer and model is the wireless keyboard and mouse? What have you tried so far? Have you tried to install any drivers and did it work or not (obviuosly not)? Do you have a manual for the keyboard and mouse? Driver CD/DVD? Do you have a little USB adaptor with the keyboard and mouse?