Hi,

I have a question about the best practice in coding a custom promotion for EPiServer 10, Commerce 10.8.0.

 
The promotion needs to provide a user specific percentage discount (e.g. 10 pct. discount) on the order,
if a specific user specific combination of products are added to the basket alongside a campaign code.

So I need 

1. to able to inspect the line items of the basket
2. to see if a campaign has been applied
3. apply an overall percentage discount to the basket

I would be pleased if you could point me in the right direction, i.e. api/classes and/or documentation?

Thanks

Michael