You've got the right idea, but:
1. Your loop won't work because you're basically saying "when the game starts, for each tilemap object do this". There's a single tilemap object in the layout so it's only going to run once.
2. The "set tile" grabs a tile by number on the tilemap object and not by X/Y position in the layout. So instead of doing what you're doing, you have to do this:
Hope that helps!
Edit: My mistake, in the loop I used "from 1 to 53" but it should really be "from 0 to 52" since 0 can also be a tile position in the tilemap. I uploaded a new image and edited it.