There are two types of BOMs a user can create within Brahmin Solutions.
Product BOM - This allows you to create a BOM for all the variants underneath the product. This would apply to all variants with the flag set to "Make".
Variant BOM - This is a variant-specific BOM where this recipe / BOM only applies to this specific item.
When to use Product BOM vs Variant specific BOM
Use Product recipes when all the variants in the product grouping are similar items and there are only a few changes needed. If the variants are highly customizable, then variant-specific BOM would make sense.