Yes you can and should plant them now. The depth should be 3x the height of the bulb.

Most certainly plant the snowdrops outside now. Are the hyacinth bulbs to pretreated ones to flower early, if so they need to be planted in a container and kept in the house; otherwise go ahead and plant in the garden.

Thank you for replying Bathgate and Moon grower. The hyacinths are for outside, Moon grower. I bought both lots of bulbs but there was no instructions. x

Just a warning - snowdrops grown from bare bulbs often don't flower in their first season so don't panic if you don't get any. Best time to plant snowdrops is while they still have leaves on just after flowering and you can sometimes buy them like that or cadge some from a friend. Its called planting "in the green"