Beginner's guide to ETFs

All ETFs are not created equal. If you are going to be day trading ETFs, there's not much to learn. My presumption is you are not going to be doing that.

So - the first step is to understand the different ways the products are structured, for example ETFs & ETNs aren't the same at all. They have different risk profiles (ETNs are more risky), they have different tax profiles too.

There's a good book called "The ETF Book" which explains all the types and the different tax implications of each type.

If you intend to buy commodity based ETFs that go out & buy Futures contracts, then you also need to understand the way the underlying futures contracts work and how they roll from one month to the next. You also need to understand concepts such as contango and backwardation because the returns on a commodity based ETF is going to be impacted by this as much as it is by the price in the underlying.

In terms of investing in a commodities through ETFs, there may be more merit in buying an ETF that (for example) invests in Gold companies than Gold futures.

You need to understand the fees & dividends too.

I'd get the book I mentioned. It's got all the info you need.