Create a Form to Build a Document

[Wordsquirrel]

Hello word world,
just want to create a form which a user can enter a few frequently used terms (like cross-references/bookmarks). These terms will get entered throughout a document.

It's easier in example:


The Document describes a design which has slightly different parameters. In the Form, a line will say "Enter the number of wells". They enter "five", and the word "five" is put in all the predetermined slots throughout the document template. Like the sentence "this design has [five] wells".

I am sure it's easy, I just can't find a guide to creating this type of form using google.