What ever brand of epoxy you use, you have to follow their recommendations, I.e is it a deep pour(greater than 11/2” deep). You can use good quality packing tape but I prefer Tuck tape myself. The measurements for ratio hardener to resin are extremely important in order for the epoxy to settle. As far as adding color that is really easy you don’t need much. The stirring to get rid of bubbles is very important and also either a hair dryer or heat gun will help (not too hot and close with the heat gun)
I would recommend start with a small project and have fun.
P.S. you can find a calculator for the amount of epoxy require for your project, it is important because if you mix too much, it will be wasted and epoxy is not cheap.