they will take it all from the default. in the conditions you only overwrite it. this is good if the OPC UA server has like 60% correct data (default case) and then with the conditions you can bring it closer to what you need (e.g., move a folder additionally, add a new asset, etc.) this should lead to something that is maintainable as the resulting logic should be easyly readable and maintainable. it will be like

copy everthing into this asset (default), 
- but if its in a folder called "folder1" then put it into a sub-asset
- but if it has "folder2" in its name, put it into another sub-asset
etc.

then when you add something to folder1, it will automatically be moved into the correct sub-asset as it matches the rules. the alternative approach is to select the asset for each individual nodeid, but that is not scalable.