# Concepts

How the chains and wallet-cli work underneath the commands. Read these once and the command pages stop feeling arbitrary.

| Concept | What it explains |
|---|---|
| [Networks](networks.md) | Canonical CAIP-2 network ids and their aliases, the two chain families, how a command picks a network, and the two fee models |
| [Accounts and HD wallets](accounts-and-hd.md) | Seeds, derived accounts, one address per chain family, account types, the active account, backup and delete |
| [Energy and bandwidth](energy-bandwidth.md) | TRON's fee model and why `stake` exists |
| [Security model](security.md) | Key storage, secret handling, recovery, and what remains your responsibility |

Doing rather than understanding? See the [guides](../guide/index.md). Looking up a command? See the [command reference](../commands/index.md).