A simple way to copy your files from a Windows PC or Mac computer to your Android tablet or smartphone, is by using ES File Explorer on your Android mobile device. No USB cable is needed.
Assuming that both your computer and Android mobile device are in the same network. Here're the step:
On Your Android:
1) Go to Google Play Store and install ES File Explorer
2) Start ES File Explorer, swipe right to get the Fast Access menu from the right.
3) Select "Network", "Remote Manger"
4) Press the "Turn On" button to turn on the FTP remote access. It shows you the FTP address to use, such as ftp://192.168.1.51:3721/
On Your Computer
5) Start Windows Explorer, type the FTP address on the address bar (as above)
6) You are ready to copy files to your android device
For a selection of options to copy to your device memory or your sdcard, go to ES File Explorer's Settings, Directory Settings, Home Directory, Go up to your device's root.
From your computer, you can browse to the folder "mnt" of your device to gain access to device's internal storage or external sdcard storage.