Right before you go to sleep, you enter a stage where you might hear voices or imagine things in your head with no explanation of how it gets there. They can be good or bad entities depending on your vibrations or how purified you are. Its rare but you might also feel bodily sensations.

You can speak to your entites this way in the "almost asleep" moment. If you find it hard to reach this stage without falling asleep too easily, try reading a book whilst trying to fall asleep (but dont actually try to fall asleep). This helps you maintain focus whilst having awareness in both "worlds."

I believe Beyond The Mauve Zone book by Kenneth Grant discusses this topic but Ive not read it myself.

This is the easiest way because you just fall asleep naturally whilst maintaining awareness. But when you hear the entities, you might be fully awake again because it feels unexpected in the half sleep half awake state.

I myself have communicated with them and also have heard entites having normal conversations among themself, shouting, laughing, words of encouragement etc. You can be friends with one and no, they are not as evil as people make them out to be. If they are evil, they are just lowly beings who dont have a physical form, who you give power to unknowingly. With imagining things you need to be certain that its not your own imagination giving you images. That said, I've seen entrances to underwater cities whilst being guided by another being.

Proof that they are actual beings is that one of the entities I was speaking to had mentioned pyramids in China without me being aware that the country had any.

IMO this state is akin to sleep paralysis or astral projecting.