This is quite a big area to cover; I would suggest that you work through the Fixed Asset manual for the different options. I have found that the best way of using the insurance granule in Navision is split the process into two. The first being the accounts payable invoice which I enter as you would any other purchase invoice.
The second is to allocate the insurance premium, using an insurance journal to allocate the insurance premium over the applicable fixed assets (there is no GL integration with insurance journals). I think this method is the quickest, especially as there could be a segregation of duties between the account payable function and maintaining the fixed asset register.
Hope this helps.