1. Put the cursor at the start of what you want to delete
2. Press F8
3. Click at the end of what you want to delete
   You have now selected a block of text
4. Press Delete

1. Put the cursor where you want to start the insertion
2. On the Insert tab, select Object > Text from file
   This opens the Insert file dialog
3. Select the file you want to insert, then click on Insert

If the styles and formatting on the document you insert don't match the document you started from, you'll need to tidy them up. Everyone using Word needs to know about styles.

An alternative to Insert > Object, if you're only inserting a page or two of text, is to use the click, F8, click technique to select the block of text you want to copy. Go back to the document you started with and paste the copied text in.
If the styles and formatting of the text you paste in don't match the document you started from, you'll need to tidy them up – using Paste special can help reduce the mess. Everyone using Word needs to know about styles.