Early exit fees

Hi quite new here, if I invest in the 5 year market but say I need my money a;d assuming I can sell out at that point, do I lose all my profit (interest) or will I only pay fees on the remaining money still invested? I find it really confusing as to how the fees work, as I understand it the 5 year account is paid back monthly, how do sell out fees work on the 1 year account?

Thanks