What you need to do is to index through every timetable. Since data is a structure, you can use fields command to get all of the fields inside data, and then index through each timetable. This looks like the following.
field_names = string(fieldnames(data));
for i = 1:length(field_names)
curr_timetable = data.(field_names(I));
%input logic to handle timetables here
end
This will let you index through the starting array, and then it's a matter of looking at the variable names in the table. I believe the property you are looking for is "head" (source: https://www.mathworks.com/help/matlab/timetables.html )
