so, first download forge if the mod is forge, or fabric if mod is fabric, second you need to download the mod u like to put on Minecraft the file will be a java executable file (I think you need java also). after that, go press windows icon and r same time. type %appdata%. find the .minecraft folder. you now need to find the mods folder that forge created on your .minecraft folder. if it doesn't create one, then you can create your own. Then open another file explorer and go to downloads. click and hold then drag it inside the mods folder. launch Minecraft and change the version to the forge one READ THIS ALSO: IF YOUR PLAYING ON 1`.12.2, OR OLDER AND NEWER ONES, THE MINECRAFT LAUNCHER, FORGE AND THE MOD MUST HAVE SAME VERSION LIKE FOR EXAMPLE: YOU NEED FORGE 1.16.5, MINECRAFT 1.16.5 AND THE MOD MUST BE 1.16.5. OR ELSE IT WILL SEND A MESSAGE WHEN MINECRAFT LAUNCHES. ITS SAYS LIKE " Ancient warfare needs 1.16.5 "