Hi,
commonly in LCA, we assess more than one impact category like in PCF. Hence, to use PCFs in LCA is not really working you could ask for EPDs that would be more helpful. To use primary data in openLCA, you just create a process with the product flow being your product. Then you add the respective carbon dioxide elementary flow in the output with the amount in respect to the PCF you got. In the downstream process, you can then add your product flow and add the respective provider.
Hope this helps