Klever is a layer-1 proof-of-stake blockchain. A blockchain is a shared, ordered ledger that records who owns what and what happened. Layer-1 means it stands on its own and does not run on top of another blockchain.
The native token is KLV. You spend KLV to pay network fees, you can stake KLV to help secure the network, and KLV moves between addresses like cash.
KDA tokens
KDA stands for Klever Digital Asset. It is the standard for tokens issued on Klever. Anything that is not KLV itself is a KDA: project tokens, stablecoins, NFTs. They all live by the same rules.
Mainnet vs testnet
Mainnet is the real network. KLV and KDAs there have real-world value. Mistakes cost real money. Testnet is a free copy of the network used for practice. Tokens on testnet have zero monetary value. Always test on testnet first.