Gesso on board is absorbent.
Sanding into colour reveals pin holes. And whatever is underneath marks the work (such as the grain of the table).
Paint bleeds, runs, colours mix and get mucky.
Paint adhesion is sometimes good, sometimes poor. When dry it can be washed and wiped back off. This is probably to do with the ration of egg to pigment. The ratio is hard to estimate.
Colours are limited to mixes from the pigments available.
Damp gesso is delicate and it tears when you scratch it, or it bubbles up and flakes off in whole layers. (Leave It Alone).
Wide brushes are good, but not for details.
A palette would be a good thing, such as the ones used in watercolour work. Also a water dropper, a dust mask, and some more pieces of plywood.