Hi all,
I am new to Unity and have just started my first project.
I have made some models in Blender which I have successfully imported into Unity, however none of these objects have any collision on them, is this something I have to do in Unity? If so, can anyone advise me on how to do it please?
Thanks in advance 
You have to add colliders to your objects. They’re under the component window in the top. Any of them should work fine. Sphere colliders are the cheapest and wheel colliders the most expensive. If you want an exact fit, add a mesh collider and select your mesh as the collider. You will also have to check convex if you want your mesh collider to collide with other mesh colliders.
i did that but still there is no collision. do I still use the OnTriggerEnter(other : Collider){} function, or i have to change somewhere