I can't find the 2nd RAM slot, in my Task Manager it says there is 1

List of Motherboards with 4 RAM Slots: ASUS TUF Gaming B760M-BTF WiFi, ASUS ROG MAXIMUS Z790 HERO BTF, ASUS TUF Gaming Z790-BTF WiFi, GIGABYTE B650 Gaming X

One single stick should work in every ram slot, no? Also, how can a single slot work in the 3-4 slot and not in slot 1-2 if it's not compatible

ramesses riches slot game slot used on 2, so I bought another RAM stick but I 2 core 4 ;logic processor with 4 gb ram Its 2021 img Jess M

ram slot 2 and 4 : 2 ram slot motherboard FRONTECH H61 Chipset Motherboard with 2xDDR3 RAM Slots LGA1155 Supports i3i5i7Pentium Processors 6+4 USB Ports