Share 'HELP ... 5 YEAR PLAN ASSET REPLACEMENT PLANS INVENTORIES WHERE DO I START?'

I have been asked by my principal ( as I still have 0.4 ICT allocated to me in my DP's role ) To put together a 5 year plan for asset replacement, register of equipment planning for maintaining and adding to existing infrastructure etc etc...... Where do I start can anyone give me an outline, framework, guide, ideas, copies that I can adjust to our school environment please help me????