How to connect external gpu?

So: I have a pretty junk laptop (acer aspire e 15) that has an integrated gpu (intel hd graphics), and now i have heard that i can connect a gpu externally, how do i know whether a gt 710 or gtx, for example 960 fits? If possible, I don't want to use an external power supply ud also don't know exactly which ports are available to me, the data sheet does not say that, what do I have to consider and check with an external GPU and which adapters do I need

So: I have quite a scrap laptop (acer aspire e 15) that has an integrated gpu (intel hd graphics), and now I've heard that I can connect a gpu externally,

that's not always possible - not even with your laptop

How do I know whether a GT 710 or GTX 960 will fit, for example?

"Fit" is relative - you will need an external housing with an external power supply

i don't want to use an external power supply if possible

You can forget

ud don't know exactly which ports are available to me

PCI Express (Mini) or Thunderbolt 3 - your computer doesn't have either, according to a quick Google search