If you haven't already chosen a spot, make sure that it is sunny and well draining. Dig every last weed out of the ground and fertilise. Have lots of mulch ready to cover the planting area - ideally arborist's ramial chips.
Space the corms at least 15cm apart and 20cm deep. Deeper planting encourages more flowers and shallower planting more daughter corms.
Each mother corm can produce up to 6 daughters that will gradually push to the surface so every few years the corms need to be dug up and spaced further apart again.
My saffron is planted in four different areas and they had all become overgrown with weeds so when the leaves died back in summer, I mulched all the beds with a combination of a thick layer of woodchips,
coffee grounds, comfrey leaves, sheep pellets,
chicken and/or horse manure - whatever was available at the time.