How do I log out and log in again to my MacBook Pro?

Question

I need to do this to restore Finale software.  I am referring to the log-in created with my name when I purchased the computer.  I am terrified of losing access to all my files!  I remember being told that there was no way to recoup this info if I lost or forgot it.  I purchased the computer in October 2011, and now have no access to the 3 year Apple support.
In addition, I upgraded to Mavericks in late October 2014.  I have lived to regret that.  I don't know what is going on with Finale, but have been told by their support that I need to follow the directions that I have copied here below.
This is the e-mail from them in its entirety.  I have not done this.  The directions that frighten me the most are #s 13 through 19 below.
I suspect I'm asking a dumb question.  But I do need help.  !!
From Finale Support (quoted):
After looking through all the information and what you are describing I believe there could be a problem related with permissions. As a troubleshooting step I would like to try the following:
1. Open your Mac's Applications folder.
2. In the Applications folder, find your Finale 2012 icon and drag it to the trash. Locate any Finale 2012 icons on your Desktop or Dock and move them to the Trash as well,
3. In Finder, navigate to Go menu > Go to Folder. Type or copy & paste the following location:
~/library/preferences
4. In your user Preferences folder, find a file named Finale 2012 Preferences. Drag it into the trash.
5. Also in this folder, you may find a file named Finale 2012 Keymaps (this may or may not exist depending on your system). Drag it to the trash.
6. In Finder, navigate to Go menu > Go to Folder. Type or copy & paste the following location:
~/library/application support/makemusic
Drag the Finale 2012 folder to the trash
7. In Finder, navigate to Go menu > Go to Folder. Type or copy & paste the following location:
/library/application support/makemusic
Drag the Finale 2012 folder to the trash
8. In Finder, navigate to Go menu > Go to Folder. Type or copy & paste the following location:
/library/preferences
9. In your system Preferences folder, find and delete these two files:
  Finale 2012 UpdateCheck.txt
  Finale 2012 InstallerVersion.txt
10. In Finder, navigate to Go menu > Go to Folder. Type or copy & paste the following location:
/library/receipts
11. In your Receipts folder, find and delete the following files:
  Any files named "Fin2k........pkg"
  Any files named "MakeMusic....Font.pkg"
12. Empty your trash.
Create a new account with administrator priviledges:
13. Quit all applications.
14. Click the Apple >>System Preferences >> Users & Groups
15. Click the padlock to make changes and enter your current Mac password.
16. Click the plus sign and create a new Administrator account. Name the account TEST and give it an easy password to remember.
17. Click the Apple menu and choose Log Out.
18. Login to the new test account using the username TEST and the password you set up in step 4.
19. Restart your computer.
20. Re-install Finale - Finale 2012 for Macintosh - https://store.makemusic.com/Downloads/Default.aspx?id=510
21. Re-launch Finale and see if the same problem persists.
Thank you if you can help.

Answer 1

Thank you so much.  I read through the entire article as well as some of its adjuncts; it was very helpful.  I believe I didn't know that was what I was looking for before you answered me.
However, when I FIRST set up this computer (while still at the Apple store, with their guidance) they had me set up what I now believe was the administrator account.  I wish I knew for sure!
They told me that (whatever it was) was unchangeable, and that if I forgot the password, I was doomed.
Is there something at a yet-more-basic (underlying) level than the administrator account?
This "memory" is what haunts me and makes me fearful of logging clear out; I never have done so.  No one else uses this computer.  But I have to log out to use the Test account (that I just created).  I DO know the password for the administrator account and the test account, as I changed them and tested them by unclicking the lock (and then reclosing it when I was.
If I still sound confused, I am  ~  woefully.  Such a basic should not be unknown to me......
Thank you so much for replying.  I hope you see this, and will do so one more time.
Respectfully,
kemandpopka