$ sfdx force:project:create --projectname sandbox --manifest
target dir = /Users/developer/workspace/clearchoice
   create sandbox/sfdx-project.json
   create sandbox/README.md
   create sandbox/.forceignore
   create sandbox/config/project-scratch-def.json
   create sandbox/manifest/package.xml

$ ls
sandbox
$ cd sandbox/
$ ls
README.md         force-app         sfdx-project.json
config            manifest
$ code .
$ pwd
/Users/developer/workspace/clearchoice/sandbox