In the past, it was common to use fine white marble with animal glue to prepare a ground for oil paintings.
Nowadays, you can buy ready-made primers like cold gesso, or if it is essential for your surface, you can spend more money and time to make your primer you can trust.
Acrylic gesso is one of the most popular surfaces for wood panels or canvases.
Use a wide paintbrush and apply two or three coats, brushing in random directions. Avoid the rough side of the gesso layer by sanding the surface between primers.
These days, you can find many cheap canvases and boards. But the only issue is that they're too absorbent. Therefore, an acrylic gesso coat of paint fixes that problem quite quickly.