Hi Qunyong,
Can you try the following steps and let me know at which step you are facing an issue?
Step 1: Download library files
library =
Import[URLDownload[
"http://dl.wolframcdn.com/0036F4/pub/WSMVirtualLabs/\
HighSchoolBiology/1.1.0.0/HighSchoolBiology_1.1.0.sma"], "SMA"][[1]];
Step 2: Get the library path
libraryPath = library["SourceFile"];
Step 3: Function to open a library nb
lab[x_] :=
NotebookOpen[
FileNameJoin[{DirectoryName[libraryPath], "Resources",
"LabNotebooks",
ToString[{"PlasmaMembrane", "FoodMetabolism", "Ibuprofen",
"NaturalSelection", "HerdImmunity"}[[x]]] <> ".nb"}]]
Step 4: Open the Herd Immunity lab
lab[5]