Baritone Ukulele Strings
The standard baritone ukulele strings are lower than the standard ukulele tuning. They are tuned to DGBE (the same as the top four strings of a guitar). They also differ from the standard ukulele as they are not in re-entrant tuning i.e. the strings go from low to high.
That's the information you'll read most places. Of course, it gets more complicated than that. I get more people asking me about baritone ukulele strings than I do any other string related query. To answer the question: yes, you can tune a baritone ukulele like a standard ukulele, but you need the right strings.
You can get strings that are DGBE with the D tuned an octave higher (giving the strings the same re-entrant relationship as on a standard ukulele) and you can get strings for GCEA tuning with the G either high or low.
The only problem is that it isn't always clear what you're getting. So it might be worth contacting the person selling them to make sure what you get is what you want.