Stuck on Kaa's Riddles: Part 1 [Spoiler]

[Torrasque]

Hello. I'm stuck on that mission. I don't know where to go. Someone told me that I need to look for a tower and inside it, there is a bag I need to take. But in the game there are many towers. Which one? The one in the Forest near the river? I tried to enter but it's impossible,

[Meowkey]

https://www.youtube.com/watch?v=AqAGEhwvsuk

[Frostbiter]

what about stalkers??