Restoring The Database via phpMyAdmin

I read the manual word-for-word on Restoring The Database via phpMyAdmin. I went to phpMyAdmin in my web browser . I clicked on the [SQL] tab; however, as the manual suggests, I do not see a smaller box labeled "Browse."

I have three questions for you. My first question obvious: how do I continue if I do not see the Browse button? Secondly, this might sound dumb, but what exactly is a database? Third, when we are importing the .sql file, what dictates the file size limitation?

Thanks in advance.