The 30 x 20″ large format photo prints can be pinned to the wall (a travesty for such quality!) or put in a frame of same size (or visit a bespoke framer)
Alternatively, these poster-print proportions have been designed with the IKE* 91 X 61 cm frames in mind.
See images below for proportions.
As well as the above GIF, the images below explain the proportions.
To fasten print to mount board, use only masking tape – the sticker type, usually available from art and craft stores (rather than the ‘light touch‘ tape preferred by decorators).
DO NOT USE SELLOTAPE.
Or, if you want to do a more thorough job, search ‘hinging and mounting prints’ on youtube.
The video below is a good example of ‘hinging’ technique.