Hello, Lenda -
The Evenflo company web site does offer instruction manuals for many Evenflo products:
https://www.evenflo.com/support/instruction-manuals.html
There is a section on that web page, with the heading Playards & Portable Beds. Perhaps one of the model names listed there is the model name for your Pack and Playard.
If not, then I suggest you contact Evenflo Customer Service and ask for assistance regarding the locked side rail. This is the link to the Evenflo Contact Us web page:
https://www.evenflo.com/contactus
If you reside in the USA or Canada, you will find a telephone number to call. Otherwise, you can fill out the form on that page to send as an email message.
Best wishes.