go to your files app, hit internal storage. Once there, find the file you want to transfer, long press it, it will give you prompts on the bottom. the first option is move. tap that now on the upper left corner you will see the folder icon, and internal. tap the folder icon to bring you back to the main page, then tap SD. once there create a folder for your file, or find the folder you need tap it to open, once its open tap move here in the bottom right corner. Blam. done. I hope. 😁 if you want a spare file, hit copy instead of move.