You should try downloading the ISO disk image from https://help.ubuntu.com/community/Lubuntu/GetLubuntu
, under the Standard PC section, and then the PC 64 disk standard image disk option.
Then, get a usb stick, plug it into your computer, then, using the Universal USB Installer, which can be found at http://www.pendrivelinux.com/
, select the distribution in the Universal USB installer program, select the downloaded ISO file, the USB stick(which should be large enough to hold the distribution), and transfer the ISO to the USB.
Once the program says everything is done, eject the USB stick from the computer and plug it into your tablet computer. Power on the tablet computer, access the boot menu, and boot off of the USB stick. The rest should be easy, just follow the instructions.
NOTE: If you are planning on doing a dual boot, be careful about how you partition(divide) your disk space. You may not be able to change it later. If you are not going to be storing games or pictures on your Lubuntu partition, then you should make that partition smaller than the windows partition, since Linux generally takes up less space than Windows.