Maternity allowance/ maternity pay?

hi ladies. hoping someone can help me here, I work 2 days a week and have done since November (after maternity leave from my first child before having my daughter I worked full time). I am due my second child in September and I'm at a total loss as too what I'm entitled too. My husband works as well (navy) so is well payed and so i don't want to go ahead and claim something and then not be entitalled too it and have to pay it back! is there anywhere you know where I can get the right answers etc or any help you can offer. I have tried looking on the gov website but it all just confused me and my husband 😂🤦‍♀️ thank you :)