If \(p\) is true, then \(\sim p\) is false, which in turn means \(\sim(\sim p)\) is true.
If \(p\) is false, then \(\sim p\) is true, and so \(\sim(\sim p)\) is false.
So, because \(p\equiv\sim(\sim p)\) in both cases, the statement is a tautology (always true).
If you were to put this in a table, you would have one column each for \(p,\sim p,\sim(\sim p)\). In the first column (\(p\)) you can think of \(p\) as an independent variable that can only take two values, true and false. In the next column (\(\sim p\)), you would negate the value in the previous column. And so on.
It should roughly look like this:
p ... ~p ... ~(~p)
T ... F ... T
F ... T ... F
