I first worked on my children’s Belgian ancestors years ago. When using the vital records from the 19th century, I used them the way I had other European records from the same time span. I looked in the “book” for and read through the entries for the years I thought included the person’s birth date. Then, if I had the correct person and had the names of the parents, I scanned the years before and after the birth to locate siblings.
Imagine my surprise when I found indexes interspersed in the records. I had never encountered those before. While indexes are not perfect, they would have saved me a great deal of time.
Moral-the first time you use any “new” record, familiarize yourself with the whole thing first, don’t assume that it is like every other one you have ever used.