Nobody can tell you exactly what to type because it depends on where you put the files when you downloaded them. Here's some general help...
In terminal-speak, directories are your folders. All the folders you see on your desktop are directories. The cd command stands for "change directory".
When you open the terminal you are placed in your "home" directory, which if you were to be given instructions to find might look like this...
Macintosh HD -> Users -> Your User Name
When you've opened a terminal window, type "pwd" (without quotes) and it will tell you your current path (I think pwd stands for "print working directory"

. It'll look something like this...
/Users/Anya
Your Documents folder is here...
Macintosh HD -> Users -> Your User Name -> Documents
So, to navigate there you'd type
cd Documents
To see a list of files there, you'd type
ls
Let's say you've downloaded sculptypaint into a folder called Downloaded Stuff in your Documents folder. To get from your Documents folder into your Downloaded Stuff folder you'd type
cd "Downloaded Stuff"
Note that there are quotes around this directory name. That's necessary because there's a space in the name. Alternatively, you could use the tab-completion method mentioned in the scultypaint document. You'd type cd and a few letters of "Downloaded Stuff" and hit the tab key, and the terminal will will in the rest of the name, like this...
cd Downl[tabkey]
Terminal fills in for you...
cd Downloaded\ Stuff
It uses backslash before the space, which accomplishes the same thing as enclosing the name in quotes. Now type pwd and you'll get...
/Users/Anya/Documents/Downloaded Stuff
If that's where you put the sculptypaint files, you'd get to the sculptypaint directory by typing
cd sculptyp[tabkey]
Terminal fills in
cd sculptypaint07.app
Now if you type pwd it'll tell you
/Users/Anya/Documents/Downloaded Stuff/sculptypaint07.app
Wrapping it up, to get to this directory you'd type
cd Documents
cd Downl[tabkey]
cd sculptyp[tabkey]
Make sure you are in the right directory by typing pwd and it'll tell you
/Users/Anya/Documents/Downloaded Stuff/sculptypaint07.app
Now, according to the instructions, you type
chmod +R 777 *
That's geek-ese for "give everyone execute permissions on all files and subfolders".
If you put the files on your desktop, that'd be here (starting from your home directory)...
cd Desktop
cd sculptyp[tabkey]