How to access a cell array using loops?

Storing data in lots of separate variables should be avoided, read this to know why:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

The simplest solution would be for you to reshape your array into a matrix and access its rows/columns:

C = cell(1,192) % your cell array
M = reshape(C,8,[]);

then accessing the data that you require is trivial using basic MATLAB indexing:

M(1,:) % 1, 9,17,...
M(2,:) % 2,10,18,...
...
M(8,:) % 8,16,24,...

Note that you can easily access the data in a loop:

for k = 1:8
    M(k,:)
end

or split it into a cell array of cell arrays using num2cell.