Assume your balance is the number of validators within your pool.
Your maintainer will be giving allowances to the Node Operators, and meanwhile, the Node Operators will compete to get as many validators as possible.
You can think of it as ERC-20 approvals. You are approving a certain amount of validators to be run by a Node Operator.
Planet.approveOperators(
poolId,
[operatorIds],
[allowances]
);
There are number of factors to pay attention to while choosing your Node Operators: