Repeats are indicated by two dots at the double bar line. If there are separate endings for first and repeat these are shown by a line above the relevant bars marked 1. and 2. The second repeat final bar(s) transition into the B part. Tab repeats are almost always simply a return to the opening bar of the part. Music notation has a wider range of possibilities and specific markers/symbols to indicate these variations.

It would be worth acquiring a basic notation guide that will explain these markers clearly with examples. These basics can be learned very quickly. Tab uses only a very few markers borrowed from standard notation.

Are you talking about tablature or staff notation?

If it's the latter (and the goal is to apply it to the 5-string banjo), there are plenty of method books that walk you through the basics. Mel Bay's Banjo Method: C Tuning - Concert Style is still in print, or you can easily find used copies of the old pink- and blue-cover editions. 

For plectrum/tenor banjo there are some method books (mostly from the 1920s) that you can find digitized versions of. 

You will not find books of fiddle tunes that teach you how to read on the banjo. 

The key is just to do it, and stick at it. In the beginning, working through a new piece is tedious, but the benefits surpass any amount of "studying" notation as an isolated subject. 

(And if you actually mean tablature, my advice is the same -- just learn pieces, and it will come to you over time). 

#1. You need to put up an example of what you are having trouble reading.

Tab is typically amateur generated, that is, there are no rules other than the basic structure of one line per string. It has evolved enough that creators tend to follow the basic rules of notation, for the most part, but there's lots of it out there that has been created in ignorance of formal music structure and symbology. Some of it even ignores time signature. It simply depends on the originator's intent.

The general rule for repeat (if there are no repeat bar lines) is that each section usually gets two repeats. AA-BB, etc. When you've reached the last section, you go back to "A". Usually if there is something different needed, there should be a note. In performance, the performers decide on the structure...and it can vary widely.

When I create Tab, I use all the standard notation tools. Repeat signs, Italian directions, rehearsal marks (alphabet), etc.

Even a few lessons with a teacher will pay off in spades. Try it, you won't be disappointed.

I picked up a book "How to Read Music" and spent part of an evening getting the low down on the low down. It had all the music info I cared or wanted for banjo. I use it some when I want to convert a folk song into banjo tab. Months? Naw, not that complicated. banjered