With the three blades on the inside of the tube hold the crimper against the inside corner of the tube and squeeze.
How to install gutters on a metal roof.
This option is preferable since wall gutters that are used on seam roofs are the task of professionals who cover the roof of the house.
A gutter cover or gutter heating system might be just what you need for your metal roof.
Either way the gutter brackets should clip around the top of the half round gutter length to hold it securely in place.
If you are using metal materials you may need to slide the gutter into the gutter brackets from the opposite end.
Crimp three times across both long edges and twice on the narrow sides.