Place the head flat against your cheek and then drop the handle so there is about a 2 mm gap between the back of the razor head and your cheek. Don't be tempted to use paint scraper blades they look the same but definately aren't. Best place for blades is Connaughts and their turnaround is about 2 weeks. There may be someone near you that can give you say 5 blades which will more than see you out til you get some from o/s.
An SE is not a DE. Obvious I know but come in from the sides under the nose not straight down. Little to no pressure and don't try to remove everything in one pass or you will suffer burn or irritation from pressing too hard. Sounds like you have acquired a 1912. They feel quite aggressive and you may find it a challenge to start with but they are actually more noise than aggression in my opinion.
All the best, they are a sensational shave and only a short step away from a straight
Steve