Perpetual Protocol uses cross margin, which means your funds are kept in one pool and all of your positions use this pool as collateral. Learn more about margin.
This makes managing your collateral easier, since you don't need to add or remove margin for each position.
Using cross-margin, one position can affect your other positions. If you have several highly leveraged positions, one position being liquidated can cause others to be at risk and face possible liquidation as well.
If you want to use isolated margin, you will have to create separate wallets. If you plan to do this, it is fairly simple to achieve using MetaMask and (recommended) a hardware wallet. Use MetaMask to select different addresses from the hardware wallet, one for each of your isolated positions.
An account's position health is shown to the right-hand side of the app's homepage by the colored lever and a message that indicates low, moderate or high risk for your position(s).
When the margin ratio is above 50%, the position health lever is green (indicating low risk of liquidation). If the margin ratio is between 6.25% and 50%, then the status is amber. Below 6.25% and the status is red.
As the margin ratio falls and the account leverage increases, the position health deteriorates, going from green to amber then to red once the account is nears liquidation.