<!-- from fixya rte -->How to install danco 3S-10H/C - Danco Faucet Stem

Turn off the water supplying the faucet. Now open the faucet. Remove handle by taking off index button and removing screw. You may need to purchase a handle puller, 10-15 dollars, and a stem wrench set. After removing handle, place appropiate sized wrench on stem and turn counter clockwise. Before installing stem, make sure it is in the open position. You may need to use the handle to turn the new stem. Screw in clockwise.

You must install the InnoTab 3S version of Learning Lodge. If it doesn't automatically install, you can install from setup files on the VTech website. Download the manual at http://www.manualslib.com/manual/551479/Vtech-Innotab-3s-The-Wi-Fi-Learning-Tablet.html

Change the O rings in the mixer.

It sounds like you might be missing a part. Check your list for all included parts. All parts are critical.

If teflon tape was used, most likely the base casting split as overtighting can occur.

I would try to find a 3/8 to 1/2 NPT adaptor on Amazon.
If Danco has a website, it's likely that the instructions for your model are available in the support section of the website.

http://kitchen-bath.hometownhardware.com/Faucet_parts-ssd70982-p9-l1-t1-Sv-dirasc-PP10.html

The same part works for both Hot & Cold sides. Usually preset to work on Hot (counter clockwise on, clockwise off). To set for Cold, simple remove the plastic clip from the top, slide the ring tab off, flip it over and put back on (you can only put it on one way since there's a flat "key" in it matching the stem) Now its set for Cold (CCW of, CW on). HTH

One of two things has happened. I'm assuming you only get hot water when you open the valve and that this is for a single handle control shower fixture. If so either this is the wrong valve for your shower control or it is installed backwards. Sometimes the valve can be installed at either 180 degree angles. See if it can be installed any other way. If so this may solve the problem.