200 Hpdi fuel pump problem

[Fightin Irish]

I have changed all my fuel filters yearly I was changing the filter in the vst tank and the fuel pump fell out of the top lid I pushed it back into that coller but it wouldn't stay up in the lid. I got it to stay put the vst tank back together but now it won't start or it will start but stall out in a few seconds. Can someone tell me the right procedure to install that fuel pump to the top lid of the vst tank.