I have created 2 aws ec2 instances and have been attempting to setup hot standby between them.

I'm really confused about this process of doing a base backup, copying the files over, then stopping the backup. The documentation is not very descriptive as to why or how to effectively do this. I have attempted this a few different ways, each with different strange errors when attempting to bring up the slave.

my most recent attempt went like this (on the master):
postgres@ip:/pgdata$ psql postgres -c "select pg_start_backup('backup')"
postgres@ip:/pgdata$ scp -r * postgres@ec2-slave:/pgdata
postgres@ip:/pgdata$ psql postgres -c "select pg_stop_backup()"
Then, I bring up the slave and this is the log:

LOG: database system was interrupted; last known up at 2012-10-09 18:21:00 UTC
LOG: database system was not properly shut down; automatic recovery in progress
LOG: redo starts at 0/3000020
LOG: could not open file "pg_xlog/000000010000000000000004" (log file 0, segment 4): No such file or directory
LOG: redo done at 0/30000B0
LOG: database system is ready to accept connections

Any help is greatly appreciated. I have worked with a warm standby setup before, but I have never actually created it. Feel free to answer me as you would an infant or Justin Bieber.