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To answer your questions, no, you do not need candles, or incense, or an offering. You don’t even need the sigil, though it is by far the easiest method to make contact. Some people can make contact through just the demonic enn alone but in my experience that takes time and practice.
For different methods of evocation, use the forum’s search function. It’s the little magnifying glass on the upper right of your screen. There are many different methods available all over the forum.