Android

  • Connect to same WiFi as your PC
  • Install Solid Explorer from Play Store
  • Install Solid Explorer FTP Plugin from Play Store
  • Open Solid Explorer and swipe down to Toolbox > FTP Server
  • Press on "Start"
  • Don't forget to turn it off by pressing stop button again after your done transferring

PC

  • Install FileZilla (FileZilla3.36.0win64-setup.exe)
  • Start Filezilla
  • Write in ftp:// address into "host"
  • Now press Enter
  • Now you can transfer files at fast speed between Android and PC over FTP