Ok so ive iced caked before and covered the cake aswell as covering the board so the cake fixed to the board fine.

However this time i have iced the board first as its so big, so how shall i secure the cake to the board? Do i apply some buttercream to the bottom of it?

Also i am putting a 2nd cake on top of this one, how do i secure this to the bottom cake?

Thanks/

best is a smear of piping gel or buttercream from your 2" offset spatula.. secure it with dowels if that is the question? or piping gel/buttercream always act as great glue! :] goodluck

Ive got dowelst to put in the bottom cake to stop it collapsing, so should i put a couple of dowels into the bottom cake and then put the top cake onto them to secure it?

i put a set of three or four dowels in each tier. the top cake i usually seperate it with cardboard so the dowels are supporting the cake's weight distrubuted thru the board ya know?

Yes i will be putting the top cake on a seperate board and dowels in the cake below to support the weight.