Measure in 4 inches from the end corner of.
Install gutter downpipe.
Fit the gutter in place which normally just clips in with the appropriate stop ends connectors and gutter outlet for the downpipe.
Watch and learn how and stop.
Drill a hole in the bottom of the gutter at the 4 inch mark with a 1 inch hole saw attachment to the drill.
Its easy less than 30 minutes and under 30 00 in parts.
Gutters over flows add downspout to bring water down from roof faster.
Place a step ladder under the area you are installing the downspout.