In the event of a theft (vol)) the first thing to do is to report the incident to the police. They will provide you with a receipt of your report that you will need to send to your insurers.
You need to state clearly the items stolen, with evidence of ownership if at all possible, and an estimate of their value.
Make sure you keep receipts or photos of items as proof of ownership, as the insurance company are likely to insist you provide satisfactory evidence.
In the event of burglary, possessions within the house will always be covered by your insurer up to the value you have requested to be insured for, providing you can provide proofs of existence . If you have insured valuables, they will only be refunded if you can provide a proof of existence and an invoice or valuation. Without those documents, there will be no or little indemnity.
Personal effects outside of the property are not automatically included, so when you take out your policy you need to question the insurer on the cover being offered to possessions in a barn or shed or in the garden.
Insurance cover will not apply where there is no break in or evidence of burglary, so keep your doors and windows locked as the insurer will not pay out.