How do I buy Solana on trust?

Could you please elaborate on the steps required to purchase Solana tokens through the Trust Wallet? I'm quite new to this crypto sphere and I'm trying to understand the process. Do I need to convert my fiat currency to another crypto first, or can I directly buy Solana with my bank account? Also, are there any specific fees or commissions I should be aware of? Would it be safer to use a desktop version of the wallet or the mobile app? Lastly, how do I ensure the security of my transactions and wallet? Thank you for your assistance in this matter.