Before following this guide you should also follow the guide below.

SGK V2 – Fixed issue with saving large number of item spawners causing fps drops

Go to the BP_SGKSaveGame and create a new variable called TempBuildPartSaveData and set its type to S_BuildPartSave and set it to any Array.

Next create another variable call it TempResourcesSaveData and set its type to S_ResourcesSaves then set it to any Array.

Add the highlighted nodes shown in the image below, location at the top of the image.

To add the input pins to the Set members in S_LevelSaveData node click it and in the details panel tick on the tick boxs next to the variable names.

Next copy the image below, location at the top of the screenshot.