You can find all the downloads here. I believe you are allowed to install the software 3 times under the same licence.
https://turbotax.community.intuit.ca/questions/1190054-can-i-download-a-copy-of-turbotax
However, a word to the wise. One of the few reasons to down load product on multiple computers is to use it as business software in order to do more than 20 returns. CRA specifically forbids this.
"Tax preparation service providers can’t use NETFILE to file tax returns for their clients. They have to use
EFILE."
