FTP connection is read only? How do I make it editable?

Hi everyone, thank you for reading my question.

I am using a Macbook with mac osx 10.5.8. In finder, I do Go>Connect to Server, and I put in my ftp://mywebsite.com and then I log in with my ftp account. I can see what's on my server, but I can't edit the files. How do I make it so I can delete files, make new folders and all of that?

If I log into the FTP server using dreamweaver, I am able to edit the files and make new folders. The same goes for when I use windows explorer - I can edit and make new files. :/ Is there some kind of setting that I'm missing?

Also, I've used this "connect to server" thing for my school's webhost too and it worked the way I want it to, except their login wasn't ftp, it is https://school.edu/webdav/myname to log in.

Thanks again for your help!