I am not sure what bulbs you have been given but the general rule of thumb is to plant it pointy side up like in the case of tulips or daffodils. (Think of an onion, nobbly roots at the bottom) If you are not sure...it won't hurt to plant them sideways as they will always grow up towards the light anyhow. Plant them 3 times as deep as the width of the bulb. Eg: If it is two cm wide, then plant it at least 6cm deep.

Some gardeners plant 1/3 of your their bulbs right side up, 1/3 sideways, and 1/3 upside-down. (That way you lengthen the blooming time three-fold, as by the time the upside-down bulbs have figured out which way is up to the light, the right side up bulbs will be begin to flower)

Good luck! :)

The name of the plant, Colocasia, is at the bottom of the question, Sunrose
I had to look this up on the web and it seems to be a huge, 6ft, hardy tropical aroid. A few GoYers have pictures of it (see bottom of this page) so hopefully they can pass on their experiences.

It isn't a bulb as such but a rhizome copy and paste the link below for detailed instructions on growing

http://bit.ly/gGry2E

The top of the rhizome will have concentric rings around a conical growth bud. The bottom will taper to a slender stem, which connected it to its "mother", and a scraggly "beard" of old roots may also be present.