I need to adjust it to get the shifter to once again go back into 1st and so it'll go into Park fully, right now it trips over the park prawl. I have the instructions, but I did not install the shifter. They say that because of the nature of the shifter, u may need to make periodic adjustments and I'm not sure what to adjust or how to start.
ANY HELP?

 

Adjustments are made under the car where the cable connects to the shifter linkage on the tranny. The cable has a treaded rod on the end of it. Disconnect it from the tranny and manually put the car in park. Adjust the part on the threaded rod so that the tranny will be fully engaged in park.

That is the basics, once you get under there you shouldn't have a problem.