The reservations may not already be opened for the French trains (only available 3 months before).
To go from Liège to Ploemeur, you can book a train from Liège Guillemin (Belgium) to Lorient (via sometimes Bruxelles and always via Paris Nord).
The travel will take between 6 and 8 hours, there are possible trains from ~7AM to ~11 AM.
The two trains with less connections (only one in Paris : Thalys then TGV) would be at 07h52 and 09h49.
To go from Lorient to the Residence Loisirs of Larmor Plage, you can either take the bus (lines 51 or 32) or a taxi.
The workshop will take place at different sites in Ploemeur and Guidel.
Traveling during the workshop:
We will have vans and we will pick you up at the Residence Loisirs to go to the various sites.