So you do have a "Products" tab (under each main product)
And, as I suspected, it shows MP2 CE. And you have access to the 3 Sounds download file and 1 Sounds Update. That all sounds good to me. And the info in your User Area / My Pruoducts is consistent with that.
So, what you have said is correct: starting from scratch you would
1 Run the IKPM, in the Software tab, go to MP2 and Install it
2 It should get Authorized automatically.
3 Switch to the Sounds tab, go to MP2, select ... More Options and select (Install to" to pick the destination folder
4 If you have SampleTank 3 installed you should select its sounds library folder, otherwise create a folder named, "SampleTank 3" on a local disk (mine is L:\IK Multimedia\SampleTank 3) and select that one
5 If the sounds (download and) install then starts automatically then make a cup of coffee; if not, then click "Install" to start it.
6 When done, download and install the Sounds Update.
When all done, close the IKPM.
Run the MP2 standalone program, configure its audio and MIDI settings and set its Disk path to the SampleTank 3 folder.