<p>Skip this step if you're not using additional mods. If you are, consult with your mission maker before installing any of these components. If you are a Mod creator, please visit the [Modularity and PBO Structure](http://ace3mod.com/wiki/development/modularity-and-pbo-structure.html) page for more information.</p>
Optional components supplement 3rd party mods with ACE3 features, for example:
- Optional weapon components make Advanced Ballistics possible, as well as the ability to use ACE3 weapon attachments with 3rd party weapons like RHS, HLC, etc.
- Optional tracers component brings back ACE2 ball tracers.
- Optional server component is used to load the userconfig files.
### 4.2 Which optionals should I use?
Only use the optional components that correspond with your mod-pack.
### 4.3 How to install these components?
- Inside your `Arma 3/@ace/` folder, you'll find the `optionals` and `addons` folders.
- Copy and paste the relevant `.pbo` and `.bisign` files from the `optionals` folder into the `addons` folder.
- Right-click inside `Addon Groups`, click `Create Group` and give it a name.
- Drag and drop `@ace` and `@CBA_A3` from `Available Addons` into the new Group you created inside `Addon Groups` and make sure the checkboxes are ticked.