If you are looking for a Spirit guide, you may already have one. Try using meditation to come in contact with it, ask certain questions specifically to your spirit guide and you may get an answer through meditation, you may have more connection to your spirit guide.
I would suggest learning a form of divination, like tarot or scrying. You also don't need to summon anything to learn about something, though it is possible. Older forms of necromancy was ceremonial and was done to conjure up the dead for asking certain questions. You seem new so I wouldn't try this unless your much more experienced. Though contacting the dead can be done without casting a circle or summoning them and you can use any form of divination to ask them stuff like tarot or something.
As stated above scrying and tarot. If you don't know what scrying is you can look into mirror scrying and water scrying also pendulums and tarot are good methods. Communicating with the dead I would agree is something for the more experienced in their journeys.