Improve Word/Excel document using macros

I need to make this document more efficient whether by creating an ecel document and exporting the data to the Word format or improving the Word doc itself. I would like to be able to do the following:-

1.Enter start time, end time, break and lunch time and have the document automatically calculate and display the times on the left according to minutes given on the right.
2. I would like to be able to edit the times if necessary and all the following times to change automatically.
3. A bonus might be to have the total mins and hours displayed.
4. The minutes on the right should be fixed but I would like to know how to edit them easily should they change.