welcome! The CO2 emissions and all the other resources and emissions that you see when you create a new database in openLCA with reference data are just "flows", which then can be used as inputs or outputs of processes to model a life cycle assessment. They do not represent any impact yet (just as the units that you also find in these referennce data are not linked to an impact directly).
You need to either create processes yourself, or import processes, e.g. from databases that you find on openLCA Nexus, which you then can enrich with own processes, to make a life cycle model and then see CO2 emissions, and impacts.
Hth, best wishes,