Assistance needed to differentiate between products

Hello everyone, I need some help with a task to expand a workflow to include an additional product. Right now, I have one product, let’s call it ‘A’, for which I load data and calculate a forecast—it’s a fairly complex workflow. I’d like to add a choice at the very beginning to select between products A and B, and then calculate the forecast for the chosen product. Some of the data is the same for both products, while some is different, but aside from the data, all the steps are identical. I’m wondering what the easiest way to set this up would be. Any advice would be appreciated.