So I can give you some advice
You want 2.5 meters high, 1.5 meters wide
Then it must be an outdoor display board
Resolution can be 60dpi~30dpi
The higher the dpi, the clearer it will be.
Many websites have material to download
You can search "material world"
When you make a display board, drag and drop the elements that look good into the file
Discharge the appropriate location
Basically, it's OK
.