Factions Immortal can become confusing without the right modifications. Which is why you have a few options on what to do: You can either use the normal minecraft launcher with forge and some standard mods such as schematica, patch crumbs, breadcrumbs, optifine, amongst others. You could also use a pvp client such as lunar client. Or, you could use clients specifically built for factions, such as crystal client, orbit client, and falcun client.
Since there are multiple different mods available for factions, each mod serves its own purpose, and therefore each mod will have their very own list of functions. For example, Breadcrumbs are useful for cannoning. This mod displays where all your sand and tnt falls, so you can see if the cannon is working like it's meant to. Whereas Patchcrumbs is used when you're getting raided. This mod displays where the tnt will land against your walls. so you can place blocks to prevent your base from getting raided and losing all your hard work.
Another one of the most popular mods is Schematica. This mod allows you to properly locate your predefined builds/structures, such as cannons, farms, amongst others.