How to stop aggregate to the parent for Period dimension

Hello everyone,

My Period dimension has an alternate hierarchy called "YearTotal_Input", which I shared the members from Jan to Dec under it:

However, when I input the data to "YearTotal_Input" on the web form, it spreads to the months automatically:

My question is:

How can I stop this spread to the months?

And how can I stop the months rolling up to YearTotal_Input if I don't run any Aggregation rule?

Thanks and have a nice day!