Accessing my playlists

In past years I used iTunes on my IBM laptop to create a library of many songs, some bought from iTunes, but mostly copied from my CDs. From this library I created about 50 playlists. I was then able to copy the playlists onto an iPad and my iPhone. Last year my old IBM was getting slower and slower. I backed up the files and iTunes to an external hard drive and bought a new Dell Computer. I asked the Best Buy Geek Squad to transfer all my music to the new Dell The icon shows, but all the songs from CDs will not play. Also I want to modify some of the Playlists. (I still have many of my Playlists on my iPad)

1) Should I subscribe to Apple Music and find a way to copy the library of songs and playlists in to the Dell computer? 2) Will I then be able to make changes, add songs etc.? 3) Then, will I be able to copy the modifies Playlists to the iPad and iPhone?

I am not a techie and I am in my 80s.