Problem with Nextgen effects

Hello, I installed Nextgen plugin and it works perfectly except the Lightbox effect.
If I activate the lightbox effect and click on one image of my gallery, I get the picture alone in corner left.
I read on forums to install lightbos, slimbox,… I tried them all but it is still not working. I may have made errors installing the plugins because i dont know how to do with the jquery.
Could someone help me detailing all the steps to follow??
Thank you very much