Welcome here, and thanks for your interest in Finite Element Analysis (FEA) features of FreeCAD's FEM Workbench!
FreeCAD FEM has had a huge amount of new features and bug fixes in any new development version. For this reason none of the FreeCAD FEM power users and none of the FreeCAD FEM developer uses an old version of FreeCAD in conjunction with FEM. For this reasons it is highly recommended to use at least the release 0.18.3 if you would like to work with FreeCAD FEM. They can be downloaded from https://github.com/FreeCAD/FreeCAD/releases . Since there have been already lots of bug fixes for FreeCAD FEM in 0.19 development circle it is recommended to use 0.19 version of FreeCAD for working with FEM. They can be downloaded at the same place as 0.18.4 versions.
BTW: If you have older files, all FreeCAD FEM objects created with 0.17 will be loaded in and 0.18.4 version. Any older objects from FreeCAD 0.16 might or might not work in up to date FreeCAD.
If you have Problems in setting up a working FreeCAD FEM Workbench or in creating a simple FEA check out FreeCAD's FEM example file FEM_CalculiX_Cantilever_3D first. Further installation instructions could be found at FEM Install. The FEM documentation may help too. See FEM_Module
If you would like to ask for any help in the regard of FEM Workbench by open a new forum topic please provide your FreeCAD info. Just open FreeCAD go to Help --> about and press the button copy to clipboard. Find a detailed description here
Have a lot of fun with FreeCAD FEM