Installation:
PC
Search (not in browser) "%appdata%" and hit enter(or return) on your keyboard. Go into the folder ".minecraft" and go into the mods folder (if there isn't one then make one). Drag the LTM.jar file into the mods folder. Run minecraft forge 1.8.9 (go to https://files.minecraftforge.net/ and download 1.8.9, run the jar and there you go!) and you're done!
Mac
Go into finder and hit Command + Shift + G type in the bar ~/Library/Application Support/minecraft go to the mods folder (if there isn't one then make one) drag the LTM.jar in the folder, run forge 1.8.9 (go to https://files.minecraftforge.net/ and download 1.8.9, run the jar and there you go!) and you're done!