editing a song

I am new here. I use win10 and audacity version 2.3.3. also ı am very amateur about using the program. I want to make a loop ( the entrance melody of a song , it is nearly 20 second long ) and I want it to be 1 minute long. How can I do that? Also is it possible to delete the lyrics and just listen the whole melody of a song ?

Select the part that you want to loop, then apply the “Repeat” effect (see: https://manual.audacityteam.org/man/repeat.html)

Probably not, but you could try the “Vocal Reduction and Isolation” effect: https://manual.audacityteam.org/man/vocal_reduction_and_isolation.html