Hey there @ciberlover7
Well first of all, welcome to S.A & the forums and glad to read that you decided to purchase ANA.
Is it ANA or ANA 2, by the way ? Asking this just to be able to update the topic title accordingly, thanks.
Just to let you know, as a moderator on the forums, I had to edit your 2 posts in the 4th Of July Sale Topic and created this new one, thank you for using the correct topics when posting on the forums. There's dedicated sections for plugins, technical support, tutorials discussions...etc.
Now to answer your question about possible infection, you can safely download & install resources from Sonic Academy website, there's absolutely no issue with that.
What's happening with your TotalAV warning is nothing else but a False Positive detection, that will happen with many different AV Software and also archive files.
So again, no worries to have you can download & install S.A resources & plugins with total confidence 
Hope this helps & enjoy your ANA ( or ANA 2 ) plugin 
Cheers !