Pardon if what I'm going to ask might sound silly, but sometimes the basics are taken forgranted so that often it doesn't get mentioned or shown clearly in a photo for a newbie like me.

I plan on using my old 72mhz JR8103 TX and 700rx for my first electric plane which will be something like a 45" to 50" mini-telemaster sized plane weighing 32oz to 40oz..
I will be using either a 2100mah 2s 7.4Lipo, or, a 3s 2100mah 11.1 Lipo depending on the finished weight of the plane.

What plugs into where? Does the lipo battery plugs into the ESC, and the ESC plugs into the "THRTL" socket in my old JR 700 receiver? My main question is will I still then need my old familiar 4.8 battery pack to power the servos? If so, I assume the 4.8V pack will plug into the "BAT" socket in the receiver, right? Do I understand it correctly that modern 2.4 receivers only require a single onboard lipo battery which powers everything so that a seperate 4.8v battery pack would not be necessary?