Depends on the demon. Demons are not automatically evil, not all angels are good. Demons, which stems from daemon which is greek for powerful spirit, have dark energy
Dark energy doesnt mean they are evil. Its like dark matter in space. It has a low frequency. Most demons are nice to humans because we can assist them. There are different realms. I'm guessing most of you have heard of the astral realm? Demons can give their energy (which has been around for thousands of years, building up and growing on itself, to assist you. In return, they want something physical.
They dont want your soul. A soul is basically a battery. And they are gods compared to us. They dont want an ant's battery, you know But humans are in the physical realm. So usually they want incense, wine for their own rituals (demons have a sweet tooth btw)
2, how many cards are in one tarot card deck 78 cards divided into two groups: the major arcana, which has 22 cards, also known as trumps, and the minor arcana, which has 56 cards.
3, do different demons like different candles for moods (red for love etc) yes! some like different colored candles, different incense smells (some are day demons and others are night demons)
(These questions came from my discord server and the answers I provide are either my own experiences or the best I could find in resources. They might not be the same as yours and thats ok)
In my opinion if you actually had anywhere else to summon a demon Id go there for the simple fact that not everyone who summons a demon is experienced people are desperate and dont listen to warning. And if thats the case and they did it in their house and did something wrong it could lead to serious consequences so to be safe Id advise to not do it in your house. A lot of satanists dont believe in casting circles however it isnt guaranteed that you have only summoned just the one entity, there no guarantee that you summoned the right entity. So if you did it improperly in your house Im sure things will end up going wrong.
Though, not all tarot decks have the same card numbers - there are inumerous tarot decks that have more than one version of the same cards. Interesting ideas though and I do agree with some of them.