you don't have to send concrete information. CIC wants to see you have a plan for returning as soon as the PR is approved. This can include a letter outlining your plans, letters of support from family and friends who will help you until you get on your feet, research done on areas to settle in, jobs/local industries, communication with real estate agents or potential landlords, proof of savings, etc. CIC understands it's not entirely possible to have things set before moving. they are concerned about how you intend to resettle and whether it's likely you would apply for welfare upon returning.