second computer installation help needed

Hi. I am not a user. I am trying to help a friend who has somehow purchased Avast with license for 3 computers. He does not seem to have a CD. He somehow managed to get Avast running on his primary (brand new) notebook. But he does not know how to go about getting the software installed and running on the wife’s or the kid’s computers. He asked me to help him. But before making the 30 mile drive I thought I’d check out the website. Nothing is intuitively obvious to me about how to go about this. I also downloaded the manual and ran numerous site searches.
Can someone please tell me the procedure for downloading and installing a purchased 3 licensed Avast on additional computers?
Thank you,
Panaharoldo

For sure download the instalation file to each computer - copy the avastlic file to the other computer. Install Avast - doublick Avastlic - job done

Download and install the trail version from here, when the program is up and running insert the License file http://www.avast.com/en-eu/download-software

avast! 5.x: Inserting the license file into avast! Pro Antivirus
http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=475

avast! 5.x: Inserting the license file into avast! Internet Security
http://support.avast.com/index.php?languageid=1&group=eng&_m=knowledgebase&_a=viewarticle&kbarticleid=476

It is important that any previous installed AV is fully removed. You can use a removal tool to clean out all leftovers
removal tools can be found here http://uninstallers.blogspot.com/