help : extracting data to create a table (employee time sheet)

hi not too sure where to go with what I have done already but maybe a guru can help here!

Ive created a spreadsheet (bit crude so far) but serves its purpose.... The data entry of the employees rota is fine but I have to then make a `hourly cover chart` which gives at a glance how many people are working at half hourly intervals.

Ok you enter the data on the ROTA form in the format of a start and end time...

I wish to get the start and end time and get it added to the data section...which then gives a hourly chart bar graph.

if I manually add a 1 or 0 in the data section this produces the required result.

Is it possible for this to work by me just getting the data from the rota part?

Let me know if anybody could help me out with this.