Re: the second part of the OP’s question. The power poles and their kin that you see in your neighborhood are usually set in earth. Long steel tamping bars are used to compact the earth around them, which is added in short lifts until done. This allows easy replacement when needed; a cherry picker can usually pull the pole out of the ground without a lot of trouble. Or at least that’s how we always set them. Guy wires come into play when you have to hang gear on a pole, if it’s a pole at the end of a line, or if the lines turn a corner. There are various ways one can anchor a guy wire (deadman, etc.), but it’s usually with an expansion anchor.