A rainy day? and never been to an IKEA shop before?
Take the train from Amsterdam Centraal direction Haarlem.
Get of at the (second) stop, station Haarlem Spaarnwoude
There you see the new big blue store. a 5 min walk from this station.
It is only a 13 min train ride (no need to change trains) and it cost you both ways Euro 6.20. trains run every 30 min depart from platform 1
Have a nice day/Vic