Your questions are pretty much answered by the LSACD on the web instructions page:
Follow these steps for successful electronic transmission of your application.
Step 1 Download necessary plugins. (Omniform and Adobe® Acrobat Reader(tm))
Step 2 Complete and SUBMIT the Common Information Form.
Step 3 Click on the Applications button, locate the desired law school, select the term for which you wish to apply, and complete and submit your application. Make sure to use the SUBMIT button on the toolbar to save your application.
Step 4 Complete all supplementary forms and SUBMIT them, then print them out for mailing. The supplementary forms cannot be transmitted electronically from LSAC to the law schools.
Step 5 Attach your written statement(s), if applicable.
Step 6 Click on Transmit. (Note: Your application is not actually transmitted at this time. You must complete the certification and application fee screen first, which is automatically displayed when you select Transmit.)
Step 7 Complete the certification and application fee payment screen (if applicable).
Step 8 Click on the Certification Letter link and print out your certification letter (if applicable).
Step 9 Click on Complete Transmit Now button.
Step 10 You will receive a confirmation e-mail that your application has been processed by LSAC for transmission to the law school.
Step 11 Mail to the law school any documents that cannot be electronically transmitted.
Step 12 Go to www.LSAC.org
to check your application status online.