cedar wood has no effect on moths, but it makes your hoiley clothes smell nice when you throw them in the bin.
There are three things you need to do:
Buy some moth killers containing Transfluthrin, which emits a vapour that kills eggs, grubs and adults. The vapour breaks down in sunlight or rain and disperses in fresh air, so they will not treat a room, you have to put them inside wardrobes, drawers, bags and crates. They may be cheaper in bulk on ebay. Paper strips will do a small drawer or a single bag, hangers will do a crate or a couple of them in a small wardrobe.
Hoover frequently and thoroughly, especially inside, under and behind furniture, and the edges of rooms where they like to hide in the gap between skirting and carpet. Clean out your cupboard under the stairs or any storage that is not frequently cleaned.
Put all your clothes and bedding through the tumble drier. The heat kills eggs. Take them out and immediately seal them into plastic crates with a tight fitting lid, or large plastic bags (clear recycling bags are good, you can put them on stuff on hangers, starting from the top) with a moth killer inside each. The bag or crate will contain the vapour inside. If you leave them lying around they will get reinfested.
If you don't liker using chemicals, that's fine. You will change your mind after you have thrown hundreds or thousands of pounds worth of clothes, carpets and bedding away.
After about a year you will probably have it under control, but I recommend continuing with hangers in your wardrobes, and in any crates of out-of-season clothes that you have put away. Moths are attracted to the scent of a woman and will home in on any clothes that have been worn and put away unwashed, including coats. Apparently single men don't get moths much.