There are some great guides to help with this project. Besides the shared instructions on several 'tips' pages, David Kelly has a detailed step-by-step with excellent pictures. His guide is a few dollars to cover publishing costs. I like printed manuals and guides so I can jump back to things and make my own notes and pictures.

We've done more than a few TB replacements at "clinics" for folks who might not feel they are ready to go it alone. Start early and have the tools and expertise handy if something is not what you expected.

On the parts, I've had great luck just asking for a care package for specific projects like this. I usually get every part I need, us some I didn't know I needed until I got into it a bit deeper. Much more convenient than dashing around looking for something I need to close up.