I have completed a page of the film, how do I find the next page please?
Many recent indexing batches are only a single page. What does your batch indicate at the top - Image 1 of 1? or Image 1 of 2/3/4?
Do you have a project that contains a set number of images? If some of those are blank, follow these steps:
On your toolbar, click on the trashcan.
This dialog box will appear. Select "All blank entries", then click Delete. The blank entries are removed and you're ready to submit.
If that is not the case, and you are looking for the next image on the film, images are pulled at random, so the chances of you getting the next sequential batch are very, very slim. Your best bet is to head back here: https://www.familysearch.org/indexing/my-indexing and select "Find A Project" or, after you have submitted your batch, click on "Similar Batch", which gives you a different batch in the same project.