Below is for an interview in SF area.
Applied two days after the position opened. Invited to take test 473, and got result immediately by email. About a week after the position closing day, They made you a phone call first and scheduled an interview, then got an email of instruction for an interview and attached package of documents to fill ahead. Make sure you fill everything, black ink is the best, and bring everything they ask in the email.
For the interview, you first would wait for somebodies to check your documents, if everything is ok, then you would wait for the 1to1 interview. Mostly they just explained the details of the position to see if you are able to do. Such as, very long hours working each day, 6 days per week, and good fit for carrying heavy bag. They also asked some interview questions, like those you can find in glassdoor. Just be prepared before you go, and relax, and answer their questions honestly.
A day after the interview, I got an email for drug test and another background check email. Just do what they sent you to do. I went right away to the drug test after I received the email. The medical facility sent the result immediately to USPS in front of me. After couple days, I got a phone call from them to invite me to an orientation, and within some hours I received conditional offer letter with two pages of medical questionnaire. They wanted you to print it out and email back to them, I did and I got their receipt respond within a day. This is how the process go from the begin til the end in the SF area.