Adding ice to your whiskey is a matter of personal preference, and I would suggest you experiment with tasting whiskey both ways, especially if you’re still learning what you like. I like to drink most of my whiskey neat, especially softer bourbons and wheated whiskeys, but I will add an ice cube to a particularly “hot” overproof rye.  Ice can numb your palate a bit, but as it melts, the cool water will open up the flavors of your whiskey and soften it. If you like this effect but want more control over the dilution of your whiskey, consider adding a few drops of chilled water in place of an ice cube.