Disconnecter/sear:
the flat side of the bottom of the long stick thing with the hole in it goes against the back of the trigger...you'll know when it fits right.
The half-moon curved thingie goes in with the curve facing out, towards the front of the gun...should fit right on. Lining up the holes to fit the pin back in may take some jiggling but it should drop right in..
After that...it's pretty easy. I'd recommend that after you get the disconnector/sear put in and pinned, you then put the hammer in, with pin (make sure the hammer is straight up/uncocked position!)...
Flip up the hammer strut, and put the leaf spring in underneath it, make sure it seats right. Let the hammer strut down now, so it's just hanging loose. Slide on the mainspring housing a bit, up until the hammer strut is almost touching the spring plunger there...just short of the holes at the bottom lining up, so you can't put in the pin just yet. Now's a perfect time to put in the grip safety...no need to put in the thumb safety yet. Once it's in, make sure the hammer strut is aligned with the spring plunger in the mainspring housing, and just slide it up home...very little spring tension. Put in the pin, and viola, you should be good to go. Cock the hammer, put in the thumb safety.
When putting the slide on, one of the easiest ways to do it is to have the barrel in it's unlocked, open position, up against the front of the slide, with the spring guide in it's normal position (assuming you have a normal USGI-type setup and not a 1 or 2 piece guide rod thingie)..start the slide on the frame upside-down, and once the frame's on, flip it right side up once the slide is at the back of the frame. The link should be more-or-less aligned with the slide stop hole...should make putting in the slide stop a real simple job.
Hope that helps..