Your order will come with specific bulb planting suggestions on each pack. These will suggest a planting depth and, if necessary, a spacing guide and the situation needed. The catalogue entry suggests he site requirements also, so between the two it should be clear.
As a guide the planting depth of soil over the bulb for most bulbs is two or three times the depth of the bulb itself. Many bigger bulbs can be planted more deeply.
General digging of the area to be planted to remove competitive weeds and reduce local compaction is a good idea.
A dressing of general fertiliser of leaf mould dug into the soil will benefit most bulbs if it is not very fertile already. You will however also be adding zest to any weeds that then grow there!
Do try and label when you plant it should save you digging them inadvertently later.
Most bulbs dislike waterlogging, if it is heavy soil and prone to excessive wetness try to increase drainage by adding grit, but the water has to be encouraged to go elsewhere too.
A dry rest is most important for many bulbs. Tree and shrub roots help achieve this in the summer. Garden irrigation needs to be considered with this in mind.