For the first exercise, we're just descending in groups of three - down three, up one, down three, up one, etc. This is a fairly common descending approach to scalar passages.
Here, we get our first taste of "playing over the bar line", It's crucial to practice these licks to a metronome. Without a metronome, it's VERY easy to fall into feeling this rhythm as straight 16ths.
Now, things get tricky. The two added notes (per grouping) will force us into some pretty "awkward" territory with regards to feeling the triplets due to the mathematics of five against three. Practice slow, and to a metronome, as always.