How does a credit card work?

• apply credit card online
• credit card interest rates
• credit card debt calculator
• secured credit card company
• company credit report
• company credit cards
• mortgage closing costs

So I made a credit card several months ago,

And have been paying what I used in full a couple days after the "due" date.

I have no idea how credit cards work.

If I used $300 that month and It was due 9/14, then I would pay $300 on 9/16.

Is that bad?

Sometimes it says minimum payment $25 something like that.

Does that mean I should only pay like $100 instead of paying in full?

I'm so confused.

I've been paying in full the whole time

But my mom tells me to pay just a little bit more than the minimum, not in full.

Does that mean my credit hasn't been building?


Thanks

Additional Details

Is my question really that stupid to think this is not real...?

I really don't know anything about credit

And should I pay even though my bill doesn't arrive until like a week after the due date?

How does a credit card work?