A bundle is a collection of separate components sold as a single SKU. The components may or may not be stock tracked. Some businesses call this a 'kit'.
The key point to remember with Brightpearl bundles is that they are not assembled; the component parts are still, in principle, available for sale separately since their stock is not consumed by listing them within a bundle.
This allows limited inventory of components to be available to a number of different bundles which are combined only when a bundle is sold. When the bundle order is shipped, the inventory of the component parts is reduced.
The alternative to bundles is assemblies. These are groups of components manufactured into a single SKU, where the assembly process removes the components from inventory and adds inventory of the finished item.
The finished item is a stock tracked SKU just like any other product.
The list of items that makes up an assembly is sometimes called a BOM or Bill Of Materials. Brightpearl does not have built-in support for BOMs or manufacturing, but there are apps available in the App Store for this functionality.
For very simple manufacturing or assembly, you can perform manual stock corrections, or upload a stock correction CSV to do multiple corrections at the same time.
Some products need modification after a customer has bought them - perhaps engraving, painting or custom finishing. The customization process can be handled using Brightpearl sales order processing features, moving the sale through various statuses, adding information into sales order custom fields, and amending the line item description on the order.