Multiple Image Merging

[loady]

I have added a layer to my cover and i want to merge it in with the back ground, i add a layer mask and select gradient tool to do this but it will only let me do it once, i want to merge from the top and then from the left but when i go to do the second merge the first one i done disapears, i tried pressing add layer mask again but it seems to add a vector mask the second time round and adding the gradient to this just messes up the whole cover.

any ideas ?

[loady]

worked it out thanks