Inviting a family member

hi everyone, am here for some help

Am a british citizen, and am planning on inviting a family member to the UK for a visit. i had a baby in july and i would like her(my aunt) to come and spend some time with me as am on maternity leave and will have the time to take her around and spend time with her.

my question is
1, am claiming child benefit and tax credit...will it affect my application as am the one sponsoring her?
2, How much do i need to have in my account to prove i can sponsor her?
3, Will my maternity pay affect me while applying( As am not getting much) but i do have money in my accounts and alse i have some savings
4,What reason should i write for inviting her? the main reason am inviting her is to help me with the baby and also spend time with us and also to take her round as she has never visited UK before

thanks you all for your reply in advance.