Why my stems turning black?

I'm afraid it has died. You may have kept it too wet and it rotted.

What Seil said.

I'm in Minnesota December, trying this in a window that gets couple hours direct sun. Bad light here. I am struggling between too much and to little water. I have no top on the sticks. How important is that? I'm thinking they will stay warmer and more moist.

I have a ph/light/moisture meter from Menards. What is ideal for moisture specifically..?

In Minnesota now is probably the worst possible time to try and root cuttings. The hours of daylight are too short and the angle of the sun is too low for what light there is to be any good. Also, roses do not do well indoors at all. Even a healthy, growing potted rose will suffer if it is inside for a long time. I would wait until spring to try any more cuttings.

Some people cover and others don't. It will work either way. The soil needs to be kept DAMP, not soggy wet, and never allowed to dry out completely. What levels are best depends on many factors.. The soil, the humidity around the pot, the size and type of pot etc. Rooting cuttings is a learning experience. You need to experiment and try different methods until you find the one that gives YOU the best results.

For myself I do mine in the spring in 16 oz. clear plastic cups with drainage holes punched in the bottom and I use seed starter soil because it is very light weight. The clear cups allow me to see how moist the soil is and allows me to see when there are roots forming without having to tug on the canes which can break off the tiny new roots. I put the cups right outside, uncovered, in full sun with the rest of the roses. Those are the conditions they are going to be growing in so I want them to be aclimated right from the start. I don't baby them.

I had to grab the sticks when wife gave me the chance;)
Should they be left on the plant till spring instead if planning to root? They were getting really long and in the way.
This is my second try in a couple months, most have rotted. Scared to water much now..

Well if you already have them then do it but in the future wait until spring. Right now the roses are going dormant so they are not producing any growth hormones. In the spring the plants are primed to grow so the hormone levels are high. I usually wait until just after they bloom the first time in the spring. The rose is sending out lots of hormones at that time to produce new growth and a second bloom. That's the best time to try and root cuttings.

Roses should not be pruned in the fall in cold climates. Leave as much cane as possible until spring. We lose a lot of cane to winter die back but having more cane to work with in the spring is better for the roses to come back with. If something is very tall you can always stake and tie it to keep it safe from winter wind whip. Otherwise just leave them alone and prune in the spring.

Black stems = rot. Rooting roses has become my quarantine hobby. Let me tell ya, I have a very extensive black stick collection! One thing I have found that helps is to spray both the cutting and the potting medium with a fungicide when sticking, and then every week or two thereafter. Whatever fungicide you use on your outside roses will work.

Oh, someone just mentioned 50% hormone and 50% cinnamon as the fungicide for rooting..haven't tried it yet..only have 2 black sticks out of 3...