Hello, have you tried following online tutorials such as https://minecraft.gamepedia.com/Mods/Installing_Forge_mods
You must install Forge by clicking on the jar/exe file (depending on your installation), and then selecting "Install Client". Make sure you played that specific Minecraft version at least once, or the installer won't let you install Forge. Then, after installing, go into your .minecraft folder, and go into the mods folder (or create a mods folder if there isn't one), and add the downloaded mod jar file there. Then, go into Minecraft, create another custom Launch Configuration, and select your forge version. Then, you should be able to just click "Play", and the mod should be loaded in.