On a mac im unsure if you are on a mac you should mention it at the beginning

You need to download any version of forge, this needs to be the same version of the mod.
for example download the 1.16.1 from here : https://minecraftupdatedl.com/lucky-block (click start download)

Get forge for your device here: https://files.minecraftforge.net/maven/net/minecraftforge/forge/index_1.16.1.html

Once you downloaded forge open it and and download it to your Minecraft client ( you might have to restart your Minecraft and launcher)

Click play and wait for it to start up

You have to close it now and locate the mods folder by typing %appdata% in your search bar
in the list look for a file called .Minecraft and look for the mods folder.
Open the location where you downloaded the mood and put it in the mods folder