Hi Christopher and welcome!
Sounds like you are off to a good start if you already have a hull and motor.
You will find huge amounts of information on setting up boats in this website. Search the "How-to" sections and custom builds section, etc... also lots of information in the "Resources" sections.
You will be needing parts to get this boat assembled and ready to go, and I see you are in Florida. I would strongly suggest checking out Warehouse Hobbies
whobbies.com/
. They have pretty much everything you will need for your build. Tony at WHH has a great background in Gas Boats and also with the Homelites. They might actually still have some hop-up parts for them. I know for a fact they have all the hardware you will need to get your build on the water!
To answer a bit of your question, the prop end of the cable is to be fitted with a soldered piece called a ferule that couples the flex to the hard 1/4" prop shaft. Stuffing tubes are typically done with 5/16" K&S brass tubing. Some are 11/32" and have a Teflon insert (can also get all this from WHH). Hope this helps!