How to ftp to individual sites on apache2

I have VSftpd and with Filezilla can get to the main PC I am working on with Ubuntu 20.04 and an apache2 server in a Virtual box with it’s own IP#.

I need to get to each individual website which has it’s own /var/www/mysite1,2 etc folder and own apache2 .conf file.

I am not sure how I set this up while I am still working on the sites using my localhost IP not the web domain name.

I’d appreciate any guidance please.