So, your first decision is going to be whether to go from Fatima to Tomar and pick up the Caminho Portugues (I believe that's the Nascente) or follow another route that Rodrigo has posted about. It looks to me like his map does not join up with the Caminho de Santiago until Ansiao, it just heads straight north from Fatima), so I would personally not take that option.
Devido a destruição dos caminhos de Fátima e Santiago pelo Turismo de Portugal, a Associação de Amigos dos Caminhos de Fátima cessou a sua missão de ajudar os peregrinos, lamentamos mas este site foi desactivado devido as alterações no caminho. Para obterem informação sobre o Caminho devem...
www.google.com
On the Nascente, there is some forum advice
https://www.caminodesantiago.me/community/threads/fatima-to-tomar.56257/#post-632282
And Rodrigo does have advice on the connection between Fatima and Tomar as well.
The small print on that map says that pilgrims who want to break the stage into two should contact Father Mauricio in Fungalvaz at 351 926 690 327
From Fatima it would be about 20 mainly downhill kms to Fungalvaz, and then 10 into Tomar the next day. Which would be a brilliant way to have plenty of time to visit the monastery and castle complex in Tomar, which is absolutely not missable, IMO. And the town of Tomar itself is a real little gem. Looks like a great option, ksam! Bom caminho, Laurie