Confused where to start

I am pretty confused about where to start. On website, the first two courses are
Link 1.)
Link 2.)

Now when you open Link 2, it says you need to do part 1 before doing part 2. And in the same link, there is a part 1 as well (in the navigation).

Now by part 1, do you mean Link 1, or do you mean part 1 in Link 2.
And is part 1 (in Link 2) the updated version of Link 1? or are they different

(Link 1 and Link 2 stated at the start. Sorry for any confusion. There is no ambiguity in my question. You may have to read twice and open the links to understand my question)


All material in link 2 are from 2019, the part 1 in link 2 is not the same as link1.
Link 1 is recorded and updated in 2020, so do link 1.