Throw a rope and swing yourself onto the ledges to the left. Climb the ledges to the left, until Sam tells you to climb back over him, so he can throw his rope. Follow him again till you reach the branch, where you can swing yourself onto the wall.
After a cutscene, climb up to the lemon orchard. Treasure #8 is here.
Then follow Sam into a building. The door is locked. But you can throw a rope and swing outside of the window, where you swing yourself once more to the left to get onto the wall. Drop down and follow the path. The next climb point is about half way straight ahead.
Climb all the way up. At the end, Sam has to throw his rope again so both can climb up onto the balcony.
Then push the big barrel in the back in so you get deeper inside the wine cellar. Next bit is confusing. Check out the video.
In the darkness, find the big barrel that you can push or pull. Pull it all out. Then go around it and use the path that was blocked by that barrel. At the end of the path there is another barrel to pull out. It will open a window to the left corridor. Go through it. In the next room, pull the barrel under the ventilation entrance, climb up, get inside.