Ubuntu 18 Remove and install software

Hi,
I'm looking for a Ubuntu specialist
I have setup a server with Ubuntu 18 on a Digital Ocean Droplet
I have installed Webdna server version (https://webdna.us/page.dna?numero=1031) following the tuto from one guy from webdna, https://plsoftware.com.au/pdf/Creation_of_Droplet_with_WebDNA_Server.pdf
But my old licence isn't working anymore...
New licence is very expensive to me as I'm working for an association with no budget.
I'm looking for someone who could uninstall the webdna server version and install the FastCGI version?
I have already the postfix with all setup done and Let's encrypt installed.