Where to put your compost bin
Ideally, it should be placed onto an open soil base so that worms, insects and microbes can help the decomposition, as long with air and moisture. A good mix of worms is a healthy sign in a good composter.
If a soil base is not available, your composter can be placed onto a concrete base - ideally you need to add a thin layer of soil to get it started as well as adding some worms from the existing soil.
Try and position the bin so that it gets some shade in the summer months as this will prevent it from drying out and put in some layers of scrunched up cardboard to create air pockets.