I have just recieved 3 white egret orchid bulbs and planted them in a pot, instruction says water after a few weeks but doesnt seem right not to water after planting..any advice

Orchids love to be completely dried out before they are watered again, which is why their compost is very very very well drained and most often bark. What is also possible is that they need to remain dormant for a while before being sprung to life, trust me overwatering an Orhid will made them very unhappy! Follow the advice of the tin, let them have a little snooze!