I don't know if this is the right place to post this question....but here goes. I went to one of the local box stores (Menard's) and purchased a couple of 4'x4'x8' composite posts that I need to cut so I can construct a planting bed or containment area around my mailbox. I don't know what to use for cutting these composite posts. Any ideas (besides a chin saw)??? Do I need a special blade for a saw??? What about screws??? Do I need to pre-drill for screws? Special bits?