This question already has an answer here:
I am new to Ubuntu, so I am not sure how to install ClamAV on my Ubuntu which is version 12.10.
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
To install ClamAV, just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the commands below.
Once its done Type clam in Dash, and click on calmTK to start the application.
You may have to do an update. Just run
To update the program Click Here to download the file, once downloaded, go the download location, right click on the file, and choose Open With Ubuntu Software Center
And click on Update.
A quick Google search provides this tutorial from our friends at UbuntuGeek. I hope it helps.