cap deploy:setup
This will SSH to your server and create some directories in the folder you specified with deploy_to, where Capistrano will store your releases, and your shared files (e.g., logs, configs, static assets like updates, etc.). If something goes wrong with permission or SSH access, you'll see some error messages. Fix these before proceeding so you know you can actually make a connection to your server.
This should setup the following directories(if you've specified to install your app in /app_name/):
/app_name/current
/app_name/shared
/app_name/releases
The "releases" directory is where copies of all your actual code are stored.
"shared" is a place where you can put common, shared files like logs, static assets, and maybe config files like database.yml.
"current" is simply a symbolic link that points to the current release inside the "releases" directory (capistrano updates this on each deploy)
cap deploy:check
Check your local environment and your server and try to locate any possible issues.
cap deploy:update_code
Update application code