There are 2 types of vinyl application

Dry application

Ensure surface is which vinyl is to be applied is thoroughly clean
The surface must not be hotter than the vinyl.
 

Wet application

Used for Big surface areas as this method helps eliminate air bubbles on larger areas of vinyl, allows re-positioning of the image several times

Use a specialist application fluid to ensure you do not re-contaminate 

Take the application tape carrying the image and lightly position it onto the substrate.

Firmly squeegee the image down, starting at the centre and working carefully outwards
ensuring constant pressure is applied across the entire design.

Slowly peel the application tape back on itself, leaving the image in position.

Re-squeegee the image to ensure good contact
take care not to scratch either the image or the substrate

Using a fine spray dampen the adhesive side of the vinyl with application fluid 

Float the application tape carrying the weeded image onto the fluid

Gently dab the image down to achieve the correct positioning.

Firmly squeegee the image from the centre outwards to force any remaining moisture/air from under the image.