1. Live simply. Don't let the stuff I own own me. Give up stuff I don't need + some stuff I do like to free up time. For example, I have removed 4 computers from my home, which means I don't have to spend time maintaining them. I give up the power of those PCs to gain the time.
2. Live frugally. Don't buy as much stuff, reduce my dependency on civilization, waste disposal, energy sources, and my job. Do more for myself instead of paying someone else. Cook my own meal instead of eating out.
Sometimes these ideas work together: moving from a suburban house to a cheap city condominium means I save money on the mortgage, don't have to pay anyone to mow a lawn, can get rid of a car & walk instead.
Sometimes they work against each other.
If I want to start cooking all my own meals, instead of eating out, I would like a well-equipped kitchen to make it more convenient. But that means having a large enough kitchen to keep all the appliances accessible. I'd want a nice set of knives, which need to be in a knife block on the counter, instead of in a drawer.
If I want to grow my own vegetables, then I'll need land (not a condo), and various gardening implements.
Man, simplicity is complicated!