Can't Install cyanogen mod 12.1s

Hi had installed twrp 2.6.0 through twrp manager as that was the latest that the phone would install.When I tried installing twrp 2.8.3, it said unsuccessful. Then in recovery, external sd card was not detected to install cynagenmod 12.1s. Tried installing it in internal sd card but after wipe of factory, system, dalvik, cache, and factory, the zip files do not show up. How do I get around the problem and install cyanogen mod 12?

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