How to reset my input method

Hi, I've using Mac for half a year, it's been very well since the day one I started using it.🙂

Recently, I encountered a problem for my "input source" or call it "input method" for Pinyin.

I somehow maybe messed up the settings for Chinese input method, and now it's very inconvenient for me that the default or the first character for "d" is given the wrong one.

I know there is a setting which I have already enabled that will auto prioritise the chacter that often used to the former position, but this feature does not fix the problem.

To be more clear, I'd like to give an image illustration here.

When you press d under Pinyin input method, this shows up.

Basically, the character I want to be in the first place is the one that's showing in the second place in the above image. That's all I have problem with.

Thank you for all of your support and time!