I recently purchased a 8GB stick of Apacer DDR4 RAM. I installed the RAM into my B1 slot as my mobo only has 2 slots. When I boot into BIOS it only shows the stock I have in my A1 slot. Any help??? Thanks in advance!
You most definitely have a mismatch as you cannot mix modules from differing manufacturers and differing frequencies.
Apacer 78.C1GS7.AUC0B are 1330MHz and the G.Skill are 3000MHz so even if they did work they would operate at the lowest 1333MHz.
Return what you can and choose a single kit the size and frequency your MB and CPU support that are listed on the MB QVL. That way you know they are tested and known to work.
Here is your QVL: https://www.asrock.com/mb/intel/h310cm-hdv/index.asp#Memory and it is from here you should sellect your RAM.
Update your Bios and chipset if not already done so.