Some smartphone/ tablets have build in file commander program which allow user to connect Dual Driver directly and do data management. If there is no build in program, Simply go to Play store to download and install the APP - ES File Explorer or File Commander then it can be worked as well.
Below is the operation sample based on using Samsung S4 (Android 4.2.2), there might be slight differences when using different device.
Please make Dual Driver Micro-USB port connect to smartphone/tablet Micro-USB Type-B port (for Android system smartphone, Micro-USB Type-B port is normally known as charging port).
When Dual Driver is well connected with smartphone/tablet, device will be drove. As massage on screen shows from USB connector connected to USB mass storage connected it means Dual Driver has been drove in the system. When it shows /Storage/UsbDriveA, it means you are in the storage of Dual Driver.
Please following the below steps to eject Dual Driver, else there will come a caution massage that inform you USB device has been removed accidently which may cause the data missing.
Apps >Settings > Storage
Storage > Unmount USB OTG storage and choose "OK", when the massage "USB mass storage removed safely" shows, it means the Dual Driver is safely ejected.
All files >/Storage >UsbDriveA , select the file you would like to transfer, ex: PPT.
Enter /Storage/UsbDriverA/PPT select the file you would like to transfer, go to the action list button on the top right, choose Move or Copy, then it will go to My File page, choose Device storage into /Storage/emulated/0 then touch move here button on the top right to copy data to preferred folder.