Synchronize in fireftp

In fireftp, Goto "tools", click  options, Click Downloads/Uploads at the top menu,
Select
Automatic Mode.
use compress,
keep timestamps in sync
check integrity of file transfer

Select the local directory you want to synchronize, which at the first column of the local site;
Select the remote directory you want to synchronize, which at the first column of the remote site;

Click tools at the top menu, select " Sync directories and su-directories"
After comparing two directories (it may take a few minutes), a new window pop up.
You can see Sync Directories

For missing local files, you can select "Download", "delete",  "Do Noting";
For newer local files, you can select "Download", "upload", "Do Nothing",
After your selection, click "Sync" button, synchronize between local and remote directories starts.