Felipe
Hi
Ok, first, you will need to change the diffusion ontology and create new diffusion definition. Every website needs to be a new ontology or a clone of previuos defintion.
You can read about the diffusion ontology here.
But in nutshell you will need to create a diffusion_group term, and its diffusion_element as children and its database(you can create multiple databases with database model) and its table (you can create multiple tables with table model). BUT, using your own tld, you can not use shared tld as tch or numisdata, you need to create a local tld only for you, because if you modify a shared tld it will be replaced when you update your ontology.
For example if you create new term as numisdata1175 it will replace with the shared definition when you update the ontology.
Therefore, you need to create something as: myownprojecttld that it could be the name of your project or institution (usually with 1 local tld is enough for any local use, multiple websites or multiple definitions, etc). Take account that tld only accept ASCII characters, without spaces, accents or any other special character, +-_/|,. etc are not allowed, only a-z character are valid. For ex: raspa_web_site is not allowed, but you can use raspawebsite.
If you have your own tld, you can create the ontology tree in this way:

But if you don't have your own tld, you will need to create new one. In versions < 6.4 you need to create it manually in PostgreSQL database, something as:
INSERT INTO "jer_dd" ("terminoID", "parent", "modelo", "esmodelo", "esdescriptor", "visible", "norden", "tld", "traducible", "relaciones", "propiedades", "properties", "term", "model")
VALUES ('raspawebsite1', 'dd1190', 'dd17', 'no', 'no', 'si', '1', 'raspawebsite', 'no', NULL, NULL, NULL, NULL, NULL);
And create his own term description:
INSERT INTO "matrix_descriptors_dd" ("parent", "dato", "tipo", "lang")
VALUES ('raspawebsite1', 'my_raspa_web_site', 'termino', 'lg-spa');
and create the counter row:
INSERT INTO "main_dd" ("tld", "counter", "name")
VALUES ('raspawebsite', '1', 'The great Raspa website');
Of course. changing raspawebsite with your own tld
In version >=6.4 is more easy and you only needs to create new record in the Ontology main (Ontology->Ontology main) as any other record in Dédalo.

When you have your own local tld you can begin to create your own definition for your own website in the ontology tree.
The best way to do it is showing previous definitions.
Some times you want replicate some other definition, so, you can use the databe_alias or table_alias to create a clone of previous definitions.
I hope is clear, if you have more questions, tell us.
Best.