Use a program like WinRAR or 7-Zip . Right-click the first file ( part01.rar ) and select "Extract Here." The software will automatically pull data from part12.rar and all other pieces to recreate the original file.
In federal court cases (such as those in the Ninth Circuit Court of Appeals), "ER" followed by a number typically identifies a specific page or volume in the Excerpts of Record ER1062.part12.rar
. For example, would refer to page 1062 of the official case evidence. Use a program like WinRAR or 7-Zip