The Delete School button is only effective if you have entered a school in error and wish to remove it immediately. If you have already associated pupils with the school you will not be able to delete it until you have linked the associated pupils to other schools. This would normally be done using the Feeder Swapper form which is accessible from the Data Integrity tab of the Divers form on the Look-up Tables menu.
Once entered, you will be able to find the new Feeder school in the Feeder School Finder below, filtering the results by several school characteristics including Features, which are the different ways in which your school interacts with other schools (feeder, destination, competition, agent, etc.). Every feeder school can be defined in as many ways as makes sense for that school.

Adding a New Feature
Features are created and managed from the relevant Feeder Features Look Up table, and they also need to be set up in System Variables | Settings, where you will need to select the feature you want to use for each type – it can be opened to automatically show the Registrar the Source Schools whilst showing another staff member the Destination Schools. Likewise these are used elsewhere, on for example, the archive area to filter to destination types.

In order to allocate these different versions of the Feeder Finder to staff members from different parts of the school, you will need to adjust the opening arguments from Forms & Reports selecting one of the following options:

Post Feature to Feeder
If you need to quickly mark 100 schools as being your 'competitors' you may well find the new Post Feature a real benefit. It works in exactly the same way that the post data in the Pupil Finder does. Just select the schools concerned, click the 'Post Features' button, select the feature, or create a new one, and post.

Having posted you may want to see where they are. If you have recorded their post code then the Address Map will show you them. You can also filter to a feature or collection of features.