Looking for a Manual or pictures to help put back together an Avon roadster circa 2000.
You do not need a special manual and there probably isn't any. You have to identify the kind of parts that are used on the bike. Like: quill stem, coaster brake rear hub, the type of bottom bracket (square taper) and so on.
Most skills you need for this bike are the same as on any other similar bike from older times so you need to get generc knowledge about bike maintenance - directed to older bikes specfically.
There are many resources you can use, books, vdeo tutorials, the Sheldon Brown's website. There are specific questions and answers here that list such resources.
As Vladimir says specific questions for issues will generate more detailed information. The problem is if you don't know what to ask for it's hard to know what to look for. Here is some information to get you started.
Here is a diagram of a bike like - but not exactly the same as - your bike.
Here is the link to the manufacturer's page for speedsters where you can still buy a brand new bike similar to this one. Contacting them might produce information on repair documents or parts availability.
search web or YouTube for
- "rod brakes" for brake adjustment.
- "cottered cranks"