If you've never programmed radios before, let me drop this little bit of hard learned advice on you:
Step 1. Read the radio.
Step 2. Save that file.
Step 3. Now, Save it somewhere else.
Step 4. If you skipped the previous 3 steps, go back and do them.
Step 5. Make your changes to the file.
Step 6. Write to the radio.
Step 7. save that file. Then save it again.
If you hose things up, having the known good file to roll back to can save you a lot of headaches. Have watched people rush into this before and deeply regret not saving the original file.