Cool. The the about those X1 vids is since they are a lot of actual production techniques many of them can even be applied to other DAWs (with some kernoodling).
However because X1 introduced the Skylight Interface and Platinum is still using it AND many of the various views or menu items (like Step Sequencer, Loop Constructor, Process menu, whatever) have not changed or have changed very little since even before the X series you can still perform the same procedures.
As you will see in that list I provided I noted exactly which techiniques/entries cannot be performed the same way in the newer versions (I was using X3 when I made that list which is almost exactly the same as Platinum anyway). In most cases that occurs though there are still ways to perform the function. Really the ONLY stuff that cannot be done relatively easily are the sections using the VC64 because it was removed in X3. Even then you can KIND of fake those techniques but you have to set up your own routing directly within Sonar which is can be tricky because the VC64 had a very complex routing matrix.
There are whole sections about converting MIDI clips into Step Sequencer Clips and SS clips into PRV Clips and doing all sorts of wacky stuff like that which can be extremely useful for working with MIDI drum loops.
Like say you drag a loop in from your drum sampler but want to edit it in the Step Sequncer (because it's simpler to use) you can convert the default PRV clip into an SS clip, make your edits, then change it back into a PRV clip for finer editing if you want. It shows how to "unlink" clips as well so if you have a MIDI Groove Clip/SS Clip that you want to have subtle changes added to (like maybe change the Hi Hat to a Ride and add an extra kick hit or a fill) you unlink that section from the original, make your changes and now you have your new pattern without affecting the original and of course you can now use either of the clips. Essentially you just turned one loop into two loops (or three, or ten).
When I first bought Sonar those vids came free and when I first watched them I had no freaking clue what the hell most it meant... but it was an interesting look at wha tthe program could do and taught me the lingo/got me used to the interface. That got me in the "Sonar mindset" and as I learned the more basic stuff there were a lot more "AHA!" moments as I made connections.
With that timesheet though you can do something I couldn't. Pick and choose what you need. I could only watch the whole bloody things and try to hope something stuck. Took me until this year to actually understand every little thing he was talking about.
Meh... just giving you a little insight on what those vids meant to me as a beginner and now as a... well whatever the fruck I am. lol
Keep at it.