Love how many threads you're starting, you're going to be so busy 😁 which GW episode is this?
Bonsai is a pruning and tying method, not a species. So you'd treat the oak tree like any other oak - leave it outside in winter. They need a cold dormant period to develop buds and grow new leaves. Look at bonsai pots and get the biggest you can afford, with a dish. Because it's in a relatively small pot, it can't grow deep roots and you will have to water it more frequently than you think (I know you're in Scotland, but...).
The same applies for the maple. I would assume they both arrive as single sticks with a tiny amount of soil/dry roots (aka bare root whips), not in a pot. Look up how to plant bare root trees.
Oak normally grows a lot more slowly than maple, and you will learn the Japanese way of Extreme Patience, wabi-sabi, and have plenty of time to read the Sakuteiki (11th century Japanese gardening guide on both technical and philosophical matters).
Fwiw, if you want to try bonsai as a method without worrying too much, it can be easier to buy a jade type succulent. But if you're a purist this isn't Real Bonsai™. Whatever you accidentally cut off will grow back, and it won't die so quickly if you forget to water it for a week (or a month). It would have to come inside during the winter though. I have a gollum fingers jade that I bonsai'ed. Bought as a small plant in a 5 cm pot from B&Q about 10 years ago, now 40 cm across in a 25 cm pot. It would have been bigger if I'd refreshed the soil and fed it more regularly.