how can i install filezilla linux software in susi 11

I do not know what version of openSUSE, nor of SLED/SLES that susi 11 is. Please, it would help those who are trying to help you, if you would use the PROPER NAME for the openSUSE or SLED or SLES GNU/Linux distribution you are trying to use.

There is NO GNU/Linux distribution called ‘susi 11’.

Wrt to ‘filezilla’, it should be part of the nominal OSS repository in openSUSE. I assume it is part of a nominal SLED/SLES repository, but I don’t know that for certain.

Try this in a terminal with root permissions (and your PC connected to the internet):

zypper install filezilla