I'm new to this. Isn't there a slot or something in the motherboard?
not on most laptop motherboards. laptops are designed to save a lot of space and electricity, and one way to do so is to cut unused parts off the mobo to make it lighter, and cost less. Laptop customization is MUCH more limited than its desktop counterpart. for most laptops, once you buy the laptop, the most you can do is change ram and HDD/SSD. a fw models will allow cpu changes and VERY few models allow a gpu change, as gpus aren't 100% compatible with all boards on the laptop side.
Edit: Essentially, if you have a lower end laptop(just about anything under 1k$) what you have in the laptop is what you are stuck with and there can be only few changes to it one can make.