Hi there! I'm really glad you're enjoying the PlayTiles version!
First, don't worry at all if you missed the day! If you miss the meeting, you can always just go there the very next day. He shows up every day at 4:00 PM. (By the way, it's very helpful to buy the watch in the northern part of town so you don't miss the time!) Also, having a strength of 13 is great, but to actually move the library boxes, you need to progress the story by finding and talking to the editor first!
Here is a quick walkthrough to find him and the riverside bar:
- From your house, head down.
- Go left along the boardwalk all the way to the end, then head down again.
- You'll pass by the municipal sports stadium and arrive near the recreation area with the skatepark.
- Turn right towards the 'Porto' sign, then head down to reach the riverside bar area.
Just remember to be there at 4:00 PM. Once you talk to him, the boxes at the library will unlock! Let me know if you need any more help.