Hi, Beverly, welcome to the forum. It can be daunting to apply with a long list of companies, but push forward to do it. It's the best investment you can make in your new mystery shopping business.
The sign up process will get easier as you get more comfortable with it. As far as time spent, signing up with most companies takes a few minutes rather than hours, so out must have started with the hardest ones. Try a few others. One way to simplfy is to save your writing sample in Word.
And, yes, near the end of the month, very litle is posted, so the five you signed up with may have jobs in your area. Best luck and happy shopping.