Just cut, copy and paste as needed to insert the desired text. I find that too much work, personally. If not, here's how to fix up the links on the rest of your buttons. If not, maybe there is a way you can reconstruct what you did without going back to a previous lesson. Highlight the text in first cell in the button under step 1, and click on Link in the toolbar at the top of the screen.
Same hint applies here.
Highlight the text in the second cell in the step 1 navigator button. Lick on Link on the top toolbar. 4.9 Remember, the links are also set up in the Big Picture Recap at the top so that the cursor will jump to the particular step referred to. Recall that the Target option is located on teh top toolbar. Try to recall or reconstruct how you set up the link that jumps to step 1 from the Big Picture Recap.