Radical form, or surd form, means usually the simplest representation in terms of square roots. The process of simplifying usually makes use of the fact that ab−−√=a−−√b√ab=ab.
The best way to start is to find a square number which is a factor of 96. Any will do, since, just like reducing a fraction, you can keep going till you can't simplify any more and get the same result in one step or several.
Eg 4 goes into 96. So 96−−√=4–√24−−√96=424. Since 4–√=24=2, this is 224−−√224. Now 4 goes into 24 so 24−−√=26–√24=26 and that means 96−−√=46–√96=46.
If you spot that 96=16×696=16×6 straight away you can save a bit of time.