Best Practices to backup and restore for Percona XtraDB Cluster


I am newbie to Percona XtraDB Cluster. I have created 3 Node Cluster by referring your Manual.
Node 1 dedicated Machine = Donor
Node 2 dedicated Machine = Joiner 1
Node 3 dedicated Machine = Joiner 2
Node 4 dedicated Machine = Joiner 3

I am using following SST method.
| wsrep_sst_method | xtrabackup-v2 |

My question is how I should perform the backups using xtrabackup (I am not using innobackupex).
Do I need to launch xtrabackup on all Nodes - Node 1 - Node 4 and make total of 4 backups?
Do I need to launch the xtrabackup only on donor Node 1?
Do I need to launch the xtrabackup on any Node, does not matter if it is donor or joiner?

For restore, once I have the backup folder/backup image, I can restore on any Node and data will be replicated to all Nodes
or I need to perform the restore on each Node individually before starting the donor and joiners?