Hi guys!
Very, very new in using this kind of tools.
Can someone, please, guide me how can I add music at the beginning and at the end of a recording. When I say adding I’m referring to play the music and what is recorded in the same time for a few minutes (of course the music will be lower in volume, like a background).
Thank you and sorry if I’m duplicating posts here 
Hi Mapo123,
I suggest familiarity with skimming, reading and then perusing:
Getting familiar with Latency, Getting familiar with Recording Multi-track Overdub and Overdubbing: A method of creating a multiple sound track. All are from the Online Manual here at Audacity Forum.
Practice with a small 1 or 2 minute light project (don’t jump in to a lengthy project until you get a process down) while you explore possible avenues before you actually perform your desired outcome.
Remember to Save your work in a Project two or three ways:
The first two are sensible as the first is stepping through to get it right … the second once you got it right make the backup in the event you messed up the first (you can start over and learn from your mistake that messed up the first (it does not hurt to keep a pencil & paper-pad handy concerning your steps taken in learning to refer back to when correction is needed (the brain’s memory is a feeble tool to rely on))) … and the third covers the first two when you re-enter the work later and find out something occurred that does not allow the first two.
Note: After you have saved the Project initially (for example in Audacity 3.1.2: my_overdub_learning_curve.aup3) create another through the “Save as” (for example : my_overdub_learning_curve_bak01.aup3 (this a Backup file)) and then “Close” the “Project” and “Exit” Audacity. Launch Audacity again and “Open” the first and “Export” an *.mp3 (or your choice of format) and when Exported then “Close” the “Project” and “Open” the *.mp3 (or your chosen format) and “Play” it to check the work in the *.aup3 file Exported format. … When doing this of the first of the two or three of the List above occasionally and randomly Save the work of the first and “Close” the “Project” without messing with the Backup 01. “Open” the first *.aup3 file check with a “Play” and when all is fine after an integrity check continue with your work in project and when you progress to your satisfaction make a working secondary Backup (for example: my_overdub_learning_curve_bak02.aup3) without disturbing the Backup 01 (i.e., my_overdub_learning_curve_bak01.aup3) … you can then toggle the Backup saves to keep a running working error free Backup for replacement to the initial work project. Take notice that each *.aup3 file is basically redundant and decreases Hard Disk Drive Available Storage Capacity.
Until familiar with the Audacity Environment Integrity goes a long ways …
Use a lot of common sense and exercise patients … things will go smoother
The above is just thoughtful basics that can be expanded upon in the learning curve.
Hope this helps you out.
Respectfully, ZARDOZ