Quest 3.
Where is the "Kuno and Rinnal headed this way, but you don't need to follow them.
The pathway you need to go is back to the west, and up the newly activated Junp Sigil?"
That's correct, yes. You're supposed to go up the Jump Sigil.
From which area can this area be reached?
I cannot find the jump point.
It should literally be shown to you during a cutscene.
If you reached the jungle without any cutscenes then you've gone out of sequence. You need to return to the Inn and go talk to Kuno in his room upstairs.