Before you consult a lawyer to set up's will, take a copy of your passport, copy of the passport to your designated and bring with you bank books, registration documents, title deeds and other documentation regarding your assets. For shares in Thai companies should bring the company documents.
For people who are not resident in Thailand, the main principle is that assets in Thailand shall be distributed according to Scandinavian inheritance rules. In order to provide necessary documents towards the Thai courts, comprehensive documentation must be given with respect to who the rightful heir, translation of various documents into English and Thai etc. This also entails that a representative of the heirs must face the court in Thailand and give necessary declarations. The
court will appoint a trustee to implement the settlement and carry out a proper division between heirs.
This process can be substantially easier, cheaper and faster by setting up a last will.