It is unlikely you have an iPhone, and the PC doesn't have iTunes. But if so, then you definitely have to download this program, without which it will be difficult to make an iPhone with a computer. Download available on the website www.apple.com in the section "Support".
Connect your iPhone to your computer using the USB cable, run iTunes and wait until the program will detect your iPhone.
In the left menu, under Library, click Music and drag your entire music folder into the main window of the program. Or select the File – Add Folder to Library (Add folder to library).
After the music folder will be downloaded to your iTunes library, select albums or songs and copy them by pressing Ctrl+C or by clicking on the selection with the right mouse button and selecting Copy.
In the left menu, under iPhone, click on the Music icon (Music), and paste the music by pressing Ctrl+V or by right clicking in a free area of the window and selecting Paste. Will start copying music to the iPhone, and the status will be shown in the upper panel of the program.
iPhone does not perceive the music as the songs in the folders, reads the information about the artist, song title, album, etc. from the ID3 tag "sewn" in the music file. Therefore, before downloading music will not be superfluous to organize your music library.