Its very difficult to explain to someone what heroin "should" look like because it comes in many different textures, colors, etc.....but in my experience the more "vinegary" it smells, the more potent it is.
If your not sure about IVing it than just snort it. Otherwise.....
To inject heroin you need a cooker (spoon, metal bottle cap, etc...preferrably something as sterile as possible), cotton, syringe, lighter, and alcohol to keep things sanitary if you want but its not neccessary.
First put the desired amount of heroin in the cooker(spoon is my favorite), try to start small so you can figure out how potent the stuff is than you can adjust your dosages from there.
Then pull up some water into the needle(I usually put about 80 units of water for an average shot but everyones different). Then squirt the water onto the heroin in the spoon.
Then you take the lighter and light it holding it under the spoon until all the heroin is dissolved in the water.(shouldnt take too long...and you might see some impurities floating around on top of the liquid....thats whatever the cut is that was cut into the heroin.). Next take a pea sized piece of cotton and place it in the spoon. Put the needle tip into the cotton and pull the plunger up until all the heroin is sucked up into the needle.
Now all you have to do is tie off your arm with a belt or something and shoot it into a vein. To be safe you should dip the needle tip into the alcohol and rub some alcohol onto the skin with some cotton or soemthign where you are going to inject to help sterilize it. To make sure your actually in the vein(before you push the plunger down) pull back on the plunger and see if blood comes pouring into the needle. This means your in a vein and that its ok to push the plunger down, injecting the heroin into your body.
After that pull the needle out, wipe the injection site with an alcohol swab to be safe and lay back to enjoy the most wonderful rush you will ever experience chemically.