You have to dry it out really well. As it’s made by using water it is saturated and will grow mold unless the moisture is extracted.
The fresh hash you’ve collected is like mush, so it’s hard to spread and dry. What we do instead is freeze it solid, then grate it. It lands in tiny little pieces a little bigger than a powder and dries in a room very well like that.
You can keep it sandy or press it into a brick, or make temple balls that take it the extra mile and cure for a long time and get better with age. There is more surface area for the air to touch on a ball than a brick.