hi! i just want to know if you can help me find a tutorial or video showing how to make and put drapes in wedding cakes... pls i badly need it... I hope you can help me. thank you so much!

the only thing I can suggest roll it thin thin thin pinch at the top of the drap like a curtain and place on your cake it will naturally fall like it should just give it some tiny pleats at the top. More pleats at the top more of a drap through the piece

I don't know of any video, but i can give you some pointers.
First, mix gum paste with the fondant, Fondant alone may stretch and brake, gum paste alone will look to stiff.
Make small cuts instead of a big long one, that may get to heavy and fall down the cake. Cut the pieces of fondant to go from one layer to the next. Pinch one side or both depending on the design, and hide were you pinched with ribbon or flowers.
How to attach the drape depends of how you covered, simple water will do with fondant, for BC I don't know, cause I don't cover my cakes in BC.
I hope his helps, the cake in my avatar is a good example of cakes with drapes.

^love the cake that you made... can i use fondant with tylose powder for the drapes? i dont how to make gumpaste

Yes, you can use fondant with tylose added.