This may be a basic question but please bear with me
Am I correct to think that the setting for
'Don't Delete Files' = NO the replication WILL delete files on the destination and
'Don't Delete Files' = YES the replication will NOT delete files on the destination?

It's very confusing for us Brits.
And another, the 'Interval' setting? what does this mean if I set
'Time Interval' = 4hr, that the replication process will start every 4hours, if so how long will it run for?