I was issued this problem to work on and got stuck trying to clear the page and load a blank screen with text, what step do I take?

I want to add Quantity Increment & Decrement Button in my website. I want to display that quantity buttons on every quantity box.
I see a lot of solutions but i messed up when they say to make a copy of file and make new directories. Can you guys please give me the easy and affective way to achieve it?

I want to add a ‘unit price’ tab and actual price of the products like this in New Order Email template.. I’m using ‘Magento 2.4.6’
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I need to delete the products non global tier prices.

Whenever customer adds any product to the cart a gift item should be automatically attach to it.