It means that your paper has no abstract index, so you need to set up an abstract, also called abstract and content abstract, which means to extract the main points or extract the main points. It is a short article, which concisely and accurately describes the important contents of the literature, without comments or supplementary explanations.

In a relational database, an index is an independent physical storage structure that sorts the values of one or more columns in a database table. It is a collection of values in one or more columns in a table and a corresponding list of logical pointers to data pages that physically identify these values in the table.