Hello Mary,
I'm doing this already for years.
In the project bin I create a folder music.
For me the most easy way is open Windows explorer besides Premiere Elements and just drag the file from explorer to the folder in the project bin.
The manual will say: use the import function from the menu or right click on the folder an choose add media from your hard drive, but the first way of importing is for me the most easy one.
And for the rest after sending to Premiere the photos on the timeline are all seperated with the default transition. After deleting all the pictures from the timeline I drag them again to the time line. All the transition are gone now and you can choose (if necessary) the transition you like.
O yes and add as many music files to the audio track(s) as you want, but be sure you do that after completing the video part.
Take care that the default duration of a picture is about the time you want to show them (edit/preferences/general).
A lot of pleasure with your work!
Rob