Noob questions about Binance & Trading

Hello, I am learning to trade from scratch on Binance and I wanted to know if you guys could help me with a couple of questions that I have. I started with a demo account of Binance on the page testnet.binancefuture in which they give you 100,000 USDT to practice:

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1. In each operation I do, I am charged a commission of 0.8% of the amount for which I buy BTC. For example, if I buy BTC for 1000 USDT, I am charged a commission of 8 USDT. If I buy for BTC for 21,000 USDT, I am charged a commission of 168 USDT. As I saw that this website (testnet.binancefuture) differs in several things from the official binance website and I would like to know the following:

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1st. Does Binance also charge a commission for every order one makes?

1 B. Is that commission 0.8% or does it have another value?

1 C. Whatever the value, is it always the same or does it vary? (depending on the time, day or some other x variable?

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1. One day I made a purchase order for a certain amount and I saw that BTC began to lower its price, I closed the page and left it for several days. When I came back BTC had risen from 66,000 to 68,000, so I did withdraw my order and I had a profit of around 800 USDT. So I wanted to know the following:

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2nd. Can one make a market order and leave it for several days, regardless of whether the value of BTC goes up or down, and wait for it to go up to a desired value and then just withdraw it?

2b. Is there a commission associated with time? That is, if I have a market order open for too long, will I be charged something for that?

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Sorry guys I'm a noob in this, I hope you can help me.