Unzip ISTA P 3.66.2.002.7z using 7zip ( https://www.7-zip.org/download.html )
You will have a folder named ISTA-P
Go to C:\ProgramData\
Create the followind folders BMW\ISPI\Data\TRIC\ then put your freshly unziped ISTA-P in TRIC
C:\ProgramData\BMW\ISPI\Data\TRIC\ISTA-P
You can now launch ISTA-P loader.exe it will ask for registration key open the activion key file copy/paste the key
Et voila
You will need an ICOM