You must now change to the directory into which Synchronet will be installed. This is the directory you created in Step 1. If you are not installing into /sbbs and the /sbbs symlink does not exist, you will need to change the path to the correct install directory, ie:
Once the above is taken into account, it is fiendishly hard to cause an error with this step. Because of this, everyone makes a different new and wonderful error, none of which are common.
After getting this step wrong and looking for help on what could possibly be the problem, you should seriously reconsider if this is really the OS you should be using – or at least if you should maybe learn how to use the OS before trying to install software on it.