But, as one teacher told me, there are about as many ways to cast as there are casters, so feel free to check out a few different videos.
Down to basics
Delft clay is an oil-based sand that gives a very good impression. The sand (or clay) is quite expensive, but you can reuse all the sand that has not been burned in the casting.
The much cheaper oil-based casting sand that is often used in industry (see webshop) works almost as well as Delft. Slightly less smooth surfaces, but if you pack the sand really hard, the difference will be marginal.
However, there are some general principles when casting metals with a high melting point (silver, gold, brass, steel, etc.)
The metal solidifies very quickly when it flows into the funnel (ingot). A good mold is where the metal can fill the mold as quickly as possible.
The ingot must be funnel-shaped all the way down to the mouth, where the metal flows out into the mold. Otherwise it will be like a bottleneck and it will go slower, a failed casting with the highest probability., See the figure below
If you are a beginner, make the hole at the mouth quite large, about 5-7 mm, then it goes faster (it will be a little more to saw off and file away, but may be worth it in the beginning).
The mold must have air channels so that the metal pushes the air through them when it flows in. (If they did not exist, the air would have to get through the metal to get out, does not work ...).
Make air ducts where the metal will flow in last.
For example. in the video when I cast a heel ring, the silver comes last to the corners of the heel, suitably making an air channel from each corner of the ring heel in the lid. When casting a 'regular' ring, as in another video, the metal ends up last on the opposite side of the ingot, it is appropriate to make 2 channels there, one obliquely upwards from the top and one obliquely downwards from the underside, see the figure above. Personally, I think that the placement of air ducts, how many and how large, is the most difficult problem when casting. You often have to try it out and try to figure out what the metal looks like after a failed casting what went wrong.
Other things you need are a burner set (eg SIEVERT Pro 86), a gas tube (the blue camping balls, available at petrol stations), some crucibles to melt in and a holder for the crucible (check eg Silververket or Sargenta). If you are casting on the stove (like me), you also need 3 Vermiculite tiles to build a corner as in the picture above.