Mirrored Assets are synthetic assets created using blockchain technology to track the prices of the underlying assets (e.g. stocks, ETFs, commodity indices) in real markets but do NOT confer any share rights of the underlying assets. Holders of the Mirrored Assets do NOT have ownership of the real assets which the Mirrored Assets are tracking.
Mirror Wallet is built on Mirror Protocol, https://mirror.finance is the synthetic assets protocol that tracks the price of stocks, futures, exchange-traded funds, and other traditional financial assets. Mirror Protocol is what enables Mirrored Assets to be created (minted).
UST is a USD-pegged Terra stablecoin, which means that the value of 1 UST is $1 USD. To start investing, you will need to fund your account with UST.
You can either buy UST in various crypto-exchanges, or using the Mirror Wallet, you can directly purchase UST with a credit card through MoonPay service (see Funding section for more details).