To the best of my knowledge, the latest Roman Missal is NOT available online. You could possibly find one at a Catholic bookstore.
Perhaps you could find an older version oline or maybe someone has a link to one.
The rubrics are the instructions (usually in red print) which give directions and show options for the Mass. Perhaps you could ask your priest if it would be possible for you to see the missal he uses since you are curious how it ‘works’.