Where to put mods
The .pkm files go in your Banished/WinData folder. I use Steam and mine is located on my C: Drive by clicking on: This PC > Local Disc (C:) > Program Files (x86) > Steam > steamapps > common > Banished > WinData. When you play the next game, and get the start screen, go into Mods and check the ones you want to use. Then exit the game completely; then go back in to start your game. This helps prevent crashes.
If the mod is large, you may have an .rar file - not a .pkm file. You'll need to extract it back to a .pkm file. I use 7-zip to do that which is free.