I would like to know what are the basics to getting started on witchcraft and casting spells so I could get an amount of knowledge that will help my spells manifest to alter reality in some way. Witchcraft is new to me and although I may have practiced it spells never worked at all and wish I had a mentor for this
Have you done any research yourself on witchcraft? There are some books that, even though most are sometimes on the Wiccan or Pagan religion, they do have the basics on starting off.
Learning how to ground and center yourself is a start. There are some great articles on the website that go in depth and have exercises on it. Then, meditating will be good too. You can first center yourself, then ground your energy and meditate while at it, grounding is a form of meditating but learn about both so you will have a good understanding of them both. For your spells, visualization is what will really help with your spells as well.
If you don't want to read books, the website has a lot of articles that will help on different subjects.
One of the most important tools is belief. don't rush to cast spells as most of the people just want the "fun" part. Keep it slow and study magick deeply. after an amount of time when you feel ready (no, I don't mean a couple of days) start with basic spells that have little danger of backfiring. (For example summoning is not a good idea for beginners)
Remember, without having a real understanding of magick, you won't be able to improve in this path.