Hi @KangZiHao,
Could elaborate a bit on your issue.
FreeMASTER does not automatically import variables, they need to be generated (section 4.2.1 Generating variables of the User Manual).
FreeMASTER facilitates this process of generating variables by importing symbolic information either during run-time or the map/elf file. As far as I know there is no support for the first option in the MatLAB toolbox, so you need to provide the path to your map/elf file manually (section 5.2 Symbol files of the User Manual).