what should be the steps to follow to restore if all accdocs (accdocs1,accdocs2,

Do you have a backup of the data? If so I would recommend restoring from the backup.

Is this on a Virtual Machine? Are there any snapshots of the environment?

No Tim,I dont have back up of that deleted folders but Iam having back up on other servers.
I mean I am having same application on devlopement server and testing server,and using same documents can i replace "accdocs" folders in testing server with devlopement server?,
no it is not on a VM? since I installed and imported applications freshly i dont have any snapshots of the environment.

Yes you could replace , Usually in an app server farm, these files are kept in a file server and mapped (properties files). Search in wiki for "Windows share setup" or "NFS Mounting" if your environment is Unix. and usually in enterprises the file servers are backed up regurly and need not worry of the Appian instance machine(s)

No, you can't take mix server folders from different environments. You run the risk of causing serious issues and will be in an unsupported state. You must use supported methods for migrating applications between environments.