A bare repository is pretty much something you only push to and fetch from. You cannot do much directly “in it”: you cannot check stuff out, create references (branches, tags), run git status, etc.
If you want to create a new branch in a bare Git repository, you can push a branch from a clone to your bare repo:
# initialize your bare repo
$ git init --bare test-repo.git
# clone it and cd to the clone's root directory
$ git clone test-repo.git/ test-clone
Cloning into 'test-clone'...
warning: You appear to have cloned an empty repository.
done.
$ cd test-clone
# make an initial commit in the clone
$ touch README.md
$ git add .
$ git commit -m "add README"
[master (root-commit) 65aab0e] add README
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100644 README.md
# push to origin (i.e. your bare repo)
$ git push origin master
Counting objects: 3, done.
Writing objects: 100% (3/3), 219 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To /Users/jubobs/test-repo.git/
* [new branch] master -> master