Have mercy,
If you visit the uscis website there is information about FILING.
Also, if you read the forms themselves, they explain how to do it.
Visit also the FAQs on this website and "www.immihelp.com" among others.
Bottom line: These are things that you should be able to find yourself reliably and at the same time; instead of asking too many questions at different times.
recommend: Putting all applications in one envelope or two or four does not matter; they will get somewhat different/distant RD. In one envelope they will get closer dates if that is important. You may save FedEx charges also if that is important for you. This is not the end of the story. The way you assemble everything is important...it is explained in the refs above. No stapling is recommended. Photos are put in an envelope and the "A" number w. pencil on the back of the photos...........
Above all, have mercy!