Very undervalued project compared with BTCST. pBTC35A offers the highest BTC reward.

Best is to download Poolin wallet and send some USDT there to purchase pBTC35A. Inside this wallet you can stake and the daily reward is send directly to your spot wallet.
Another option is to get it from Uniswap, but then you'd have higher ETH fees.
If you have questions you could reach them in Telegram:
https://t.me/marsproject1