Every blockchain charges a small fee to process a transaction, and that fee is called gas. It does not go to Celia, it goes to the network itself, and it must be paid in that network's own coin. This is true of all self-custody wallets, not just Celia.

If you see something like "Insufficient BNB for gas" or "you need 0.003 SOL for gas," your token balance is fine, you just need a little of the network's coin to cover the fee. Buy a small amount of that coin with your Naira balance (or receive some from elsewhere), then try your action again. Note that buying crypto with your Naira balance does not require you to hold gas; sending, swapping, and selling do, because those move crypto on-chain.