Before you can able to mine BTC with a PC but right now it won't.
If you want to mine BTC you will need ASIC machines like Antminer s9 it's simple and easy to set up if you have them.

Read this "First time/Small miner reference for getting started." now if you decided to continue and want to mine BTC you can buy them directly on manufacturer's or verified distributor check this list https://bitcointalk.org/index.php?topic=5045732.0

About setup or how to configure your own miner, I think you can check this profile https://bitcointalk.org/index.php?action=profile;u=348185 under his signature you can find all guides/reviews you can use them as a reference depending on what ASIC machine you bought.

I'm looking for a good exchange that's slowly growing up, I plan to buy and hold the tokens for long term and I want to hear people's feedback on the tokens.

1. CoinEX
2. DODO
3. Bkex chain

Any contribution will be accepted

Do you mean investing in the mining hardware? If yes, I do not think that will be worth doing because we know that the hardware companies release a new graphic card almost every month and the mining companies can also release the newest hardware to mining. So maybe it will be better if you allocate your money to invest in coins such as bitcoin, ethereum or bnb. That will be worth doing since bitcoin and altcoin can increase again this year. But that is up to you because we can only suggest to you what is the recommended thing that you can do to invest in crypto.