First, you have to collect particular project files (schematic, pcb, netlist, output files) in separate directories. It’s recommended to keep the same name for directory folder, schematic, pcb, netlist.
Now, if you doesn’t have any .pro (project manager file) you need to copy default kicad.pro file from share\kicad\templates and rename it to match other files in each project folder. The default .pro file include the default libraries list, so if you’re using your own libs you should update the list. It can be done with text editor or via Eeschema.
Once you do this you need to make a full migrate of older projects to the new version. See PDF document in
for further guidance.