Well a matter of practice

Basically, the attachment of screen protectors - any kind of device - always connected with tact. These films can attach relatively well in my opinion, but I've had better products with lighter attachment.

As the accompanying instructions probably is a standard paper which is, provided for each device, regardless of screen size, description, photos and reality are not quite consistent. While in the description of red, blue and transparent film portion is mentioned, there is really only 2 and a transparent blue part.
The connoisseur will not probably bother so much, but I was the just confused. Also, I find the pictures generally not well done because they do not show exactly where, how and what needs to be done in order to obtain an optimal result. Maybe the manufacturers could consider a revision of the instructions even once.

After the first attempt was with me totally wrong, it went well the second time around without dust inclusions or bubbles. Although now a film is gone, I would shop here again because the price is right and the quality has convinced me after a successful trial.

If you do not regularly work with such films and occasionally even an installs on a device, you have probably heading for testing purposes with a wear film, but that's OK if at least one sits and looks good.