I have had some 18mm (0.7") MDF cut to make some shelving in an alcove between my shower room and main hallway. It's 18.5cm (7.2") deep by 196.5cm (77") long
I have been considering the best way to mount these to the plasterboard/drywall – there's a few screw options and i'm inclined to go with this type https://www.diy.com/departments/diall-steel-self-drilling-metal-plug-pack-of-100/1511938_BQ.prd
but I'm not sure what to actually use to mount the shelves.
Watched a lot of videos where people screw wooden batten supports against the wall and simply rest the wooden shelf on that, but not sure that will work with the .5" think MDF
p.s. found this pretty good guide – but I'm limited with my abilities and tools. https://www.practicaldiy.com/carpentry/shelving/shelving_alcove.php#metal