ISTA help

[BuntyK]

Hi everyone, its been a while since i used ISTA, i believe the last version i had was 4.2x.xx i no longer have the laptop i had this installed on.
i wanted to get the latest ISTA but i am not sure how it works now, previously i downloaded the files and just copied the PSDZ files into the relevant folders, now its doesn't seem to work like that, i am reading about a ISTA launcher etc. 
Not sure where to start. is someone able to help me find the latest ISTA 4.44.x and the launcher please?
Thank you for any help you can provide.