This is a question of your motherboards UEFI settings. I use Asus and setting TPU to 'TPU II' instead of 'TPU I' allows specifying of multiplier without manual multiplier/divisor and voltage settings. I'm not sure how it is on other motherboards, because I only have Asus boards.
You shouldn't be overclocking if you don't know how. You need to do more research. Also, remember that you are voiding your motherboard and CPU warranties when doing so.
Please provide your motherboard model if you wish for advice on the settings you should use, but remember overclocking and overvolting are not supported beyond allowing you to mess with them at your own risk on certain UEFI firmware options(what you call BIOS).
If you have an Asus Motherboard, the TPU setting will allow you to set the multiplier without manually settings divider and other related settings such as voltage.
If your RAM is not on the Memory QVL(Qualified memory Vendors List) then you may have no luck getting it clocked above 2800mhz or getting it to be stable at any clock at all. There is also other limiting factors in RAM clock speeds related to processor and motherboard - not to mention you have to find the right timings and voltages if the XMP profile is not working, assuming that your motherboard has the RAM in the QVL. Never buy memory that isn't in your motherboards Memory QVL, I've made that mistake before... 3200mhz ram, only clocks stable at 2933mhz, or with custom settings and timings 3333mhz is stable, but at no settings can I find that will make it stable at 3200mhz which it is rated for. Memory QVL lookup required always when buying new RAM and or Motherboard.