Growing trees from seed in the garden can be as a simple as taking a seed and burying it in ground! you dont need fancy equipment to achieve this but the following are useful to have:
Other than these things, you do not really need much else, just some patience!
I have found the easiest seeds to germinate outside are apple seeds in autumn. Apple seeds take about 7-10 days to germinate in slightly cooler weather, so autumn outside is a great time to give growing them a go.
You can grow seeds inside, just like you can outside. Some seeds prefer a bit of warmth, so growing them inside suits their growth better.
The euqipment you need is very smilar to growing outside - the difference is, you'll need something to grow it in.
Other than these things, you do not really need much else, just some patience!
The seeds I grow most often inside are lemon seeds. Lemon seeds prefer a little warmth to the cool temperatures of Britain outside, so a windowsill works well to help them germinate. I have also grown oak and horse chesnut trees inside just as well as in the soil in the garden.