% If you want to get a brief descriptoion of the Matlab command clc:

Syntax: help clc

% If you want to get a detailed documentation of the command clc:

Syntax: doc clc

% Supposing you do not know the function name regarding plotting, you can search the documentation in the search bar:

% You can also find the functions you need by clicking function browser - $fx$ with a tiny triangle in the Command Window:

%% Never forget Google!!!