Apple support update article (how to)

Question

the following article suggests
http://docs.info.apple.com/article.html?artnum=307128
Solution
Log in as an administrator.
Open Terminal (in /Applications/Utilities).
Type the following commands, each on a single line and followed by Return (enter an admin password when prompted):
how do you enter (2) single lines in Terminal
what is the proper way to execute these instructions
http://docs.info.apple.com/article.html?artnum=307128

Answer 1

RC
thanks so much for the clarification / explanation
i suppose the most clear way of writing this would be
Type the following commands, each on a single line and EACH followed by Return
sudo dscl . create /Groups/username GroupMembership username
Return
sudo dscl . change /Groups/username RecordName username _username
Return
VS
sudo dscl . create /Groups/username GroupMembership username
sudo dscl . change /Groups/username RecordName username _username
Return
for my learning :
re: the following example: (randomly chosen example of code)
cd /System/Library/CoreServices
sudo mv DefaultDesktop.jpg DefaultDesktopBackup.jpg
sudo cp [drag image] /System/Library/CoreServices/DefaultDesktop.jpg
chown root:wheel /System/Library/CoreServices/DefaultDesktop.jpg
chmod 644 /System/Library/CoreServices/DefaultDesktop.jpg
would each of these be typed and entered with a return?
as i am just becoming familiar with terminal only by necessity, i am learning CLI rules and procedures. As such I would have no real idea what the point would be, as I have no such knowledge yet of what is proper, and allowable.
Thanks so much for your responses.