Cut the wood. I did this with a hacksaw blade as it is easier cutting small wood that way sometimes.
Image 5 shows the poster with the wood at top and bottom. How you put the wood there is your choice.
Here are some ideas.
- Glue the paper to the wood at the back of the wood.
- Pin the poster to the back of the wood with drawing pins/pins.
- Brad Nail the wood and posters to a wall or whatever.
I have tried all of these and they work.