After you register you then have to pass all USMLE Step 1, Step 2 CK and Step 2 CS in order to be ECFMG certified.
During this or after it you can request ERAS token from ECFMG OASIS which will then let you apply to myERAS website administered by AAMC which will then allow you to apply for residency programs via the "match" administered by NRMP.
In addition to what Sabio mentioned, right now you have to start working on obtaining LORs, MSPE and Medical school transcript. You don't have to send them now but make them ready ASAP to send them as early as you buy the ERAS Token on July 1st.
Also start working on your personal statement/s (depending on how many specialties you are applying to), you will have to upload them from your computer later to MyEras system.
The most important thing to do in this time is to start searching the programs that you want to apply to, go to my website and take a look on the IMG friendly programs in different specialties.