Olá, encontrei este exemplo na NET https://www.blogadvpl.com/criar-ler-e-gravar-usando-uma-tabela-ctree-dtc, veja se te ajuda.
aAdd(aCampos,{"REV_FILIAL" ,"C", 02,0})
aAdd(aCampos,{"REV_COD" ,"C", 06,0})
aAdd(aCampos,{"REV_DATA" ,"D", 08,0})
aAdd(aCampos,{"REV_CONTA" ,"N", 09,0})
dbCreate(cArquivo,aCampos,"CTREECDX")
dbUseArea(.T.,"CTREECDX","\system\tabela123.dtc","REV",.F.,.F.)
IndRegua( "REV", "\system\tabela123", "REV_FILIAL + REV_COD",,,"CODIGO" )
dbClearIndex()
dbSetIndex(cIndice + OrdBagExt() )