It let me do the first page, but the rest of the entries (51) say not to index.
That should mean the image which is labeled such is a Reference Image. Reference Images are exactly that - to assist the indexer in determining type/date of records on the actual indexing image/batch.
You should click the Reference Image icon and go back to the batch.
If there are no more batch images to index - if it shows Image 1 of 1 there is only 1 image to index - you can Submit the batch and download another.
As genthusiast shows you, the blue bar will say image 1 of 1 if there is only one image to index. If there were more images to index, it would say image 1 of 2, (or 3, or 4 - maybe even 10!). But, you would never use the reference images to create a new record. Reference images are only used when the last entry on your image continues to the next entry on the reference image. For instance is the name of a bride and groom were on your image, but the date of marriage and their parents names were on the reference image - then you might need to look at the reference image to fill in the blanks on their record (Names, date, parents names). You really don't need to have reference images open, until you need to look at them for more information.
From your description, It sounds like you might have 51 entry forms. If that is the problem, once you have indexed everything on your image, you will need to delete the unused entry forms in order to submit the batch. To do this, click on the trash can icon (right in the center of the tool bar) and then click "all blank entries" and then the Delete Button.
It is always best to provide the URL link or the share batch code with your questions to get the most accurate answer. The Share Batch code is the series of letters and numbers in brackets at the top of the page like this: [MQMD-DGD]