Here is a simple, authentic Jain view of the 14 Rajlok (the 14 realms of the universe):

• The universe is organized into three broad regions: upper worlds (Urdhva Loka), the middle world (Madhya Loka), and lower worlds (Adho Loka).
• In total there are 14 Rajlok: seven in the upper region, one middle region, and seven in the lower region.
• The middle region is the world where beings with karma—humans, animals, plants—live. This is the only broad realm where beings can progress spiritually and possibly attain liberation with right faith, knowledge, and conduct.
• The upper Rajlok are heavenly realms inhabited by gods and celestial beings.
• The lower Rajlok are various hells where beings experience fruits of negative karma.
• The structure is often described in terms of measurement by rajju (the unit Rajlok is very large) and is said to reach 14 rajjus in height, with the other dimensions varying according to Jain cosmological models.

Notes:

• Different Jain traditions (Digambara vs. Śvetāmbara) may present small differences in details or emphasis, but the core concept of seven upper worlds, the middle world, and seven lower worlds remains common.
• Some texts also mention Siddhashila (the realm of liberated souls) as a special transcendence above the ordinary Rajlok, where liberated souls reside; this is related to the Jain view of moksha but is distinct from the ordinary 14 Rajlok framework.

You can read more here and see how the three-world idea is presented in Jain cosmology.