Make sure to review the Main Language Page
The books to be used for this language are Familia Roman & Roma Aeterna from the Lingua Latina Per Se Illustrata collection. This book should be purchased along with them: A Companion to Familia Romana.
The following links contain pdfs with grammar, readings, etc.
http://www.thelatinlibrary.com/ll1/
http://www.thelatinlibrary.com/ll2/
http://www.thelatinlibrary.com
Audios:
http://www.johnpiazza.net/svlatin_audio
Free audios: https://lukeranieri.com/audio/
Latin by the Ranieri-Dowling Method
Once you have finished the two volumes in Lingua Latina, you should then read Caesar’s Gallic Wars at the above linked Latin Library. Then I would move on to the Latin texts listed in the Greek & Latin Reading List.