here are a few helpful links to get you started:
1. how to install freebasic on freeDOS :
https://www.streetinfo.lu/computing/basics/software/freedos_fbc.html (https://www.streetinfo.lu/computing/basics/software/freedos_fbc.html)
2. about installing freeDOS on virtualbox VM:
3. how to connect freeDOS in VirtualBOX with shared folder so you can transfer files and folders from the host to the guest and vise versa :
https://git.javispedro.com/cgit/vbados.git/about/ (https://git.javispedro.com/cgit/vbados.git/about/)
4. CLUMSIER A LIGHTWEIGHT FREEBASIC IDE FOR FREEDOS
https://github.com/clasqm/clumsier (https://github.com/clasqm/clumsier)