I’m new and I have some problems

I’m new to Linux mint and I am using it on a usb drive for now and my first problem is I can’t connect to the wifi I have no way to do it wired it doesn’t come up with the option to even toggle wireless the 2nd is that made a partition in disk utility for 700gb and formatted in exfat just for Linux but when I go to install it. It doesn’t give me any clear indication one how to do it I found were it is but I don’t know how to install it and keep it there I still want to have Mac OS on my Mac (I’m not doing this on windows) because I hear that your Mac with shit itself because it doesn’t have the inbuilt os and there is too many files on the disk to transfer with just a 32 gb usb. If I need to give any more info to help me out please let me know this is my first time