Based on your original post, your manure pile is pretty much is a compost pile. The horse manure and urine are your high nitrogen materials, also known as 'greens' for ease of speaking and the pine shavings are the high carbon materials otherwise spoken of as 'browns'.
Turn your pile a few times and keep moist and observe. The ammonia smells means nitrogen escaping into the air so maybe add some more 'browns' and keep turning. Sewer smells means it needs air - keep turning things over until the smells correct themselves, back off on the moisture and maybe, wait because that's a maybe, add more 'browns'.
If it looks like it's doing a whole lotta nothing, look at the moisture part first, then turning and then adding greens.
As mentioned before, observe what's going on and adjust. Once it seems OK, just let it do its thing while you keep the moisture and air in check. At some point you stop adding things just to let the stuff already there break down into compost.
Easy to read and good reference link that helps explain a lotta things:
The link above used to be https://www.compostinfo.com/
and was changed some time in the last 6 months.