RAM SLOT 2 Doesn't work

Why my laptop task manager show 1 of 1 ram slot used but i have 2 ram slot 2 and 4 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 rama 5 lottery Boost Your Computer's Performance: RAM in Slots 2 and 4 • Enhance Performance: RAM in 2

ramses legacy slot New PC conf and I got RAM question, shall I put the memory sticks in SLOT 13 or stay with my current setup 24?