Can I add other sites to one click wordpress install and how would I do that?

You should really use SFTP all the time. FTP should never be used.

<b>“I’m not sure which of the two is the better choice for ftp, proftp or vsftpd”</b> <br> <br>Plain 'ole FTP should be your last resort. For more info. & links on installing vsFTP or proFTP, <i>see</i> <a href=“https://www.digitalocean.com/community/articles/what-is-ftp-and-how-is-it-used” target=“_blank”>What is FTP and How Is It Used?</a>. <br> <br>Where are you transferring your files, from (b/c SCP and/or rsync are more secure than FTP)?

I prefer the latter Pablo, and this is where I need the help. <br>I have set up virtual hosts in the past with no problems using sftp as my file transfer method but I would like to use plain old ftp i.e filezilla etc to transfer my files.
<br>This is why I went with the one click install on my droplet because at least I’d have a site working. <br>I’m not sure which of the two is the better choice for ftp, proftp or vsftpd, anyway thanks for butting in and I hope you can tell me how to get this working.

Yes; but, as the old saying goes … ‘There’s more than one way to skin the cat.’ <br> <br>Are you interested in <a href=“http://codex.wordpress.org/Create_A_Network” target=“_blank”>WordPress Multisite</a> or do you prefer <a href=“http://codex.wordpress.org/Installing_Multiple_Blogs” target=“_blank”>multiple, but separate, WordPress installs</a>?

Yes, it is possible: https://www.digitalocean.com/community/articles/how-to-set-up-apache-virtual-hosts-on-ubuntu-12-04-lts