After I replace the ram on my pc, is there anything else I have to do to get it to work? Download anything or go into bios?

Before you replace the ram in your computer go to the manufacturer's website and download the latest bios. Make sure that the ram that you're putting in your computer is the proper RAM for your computer. High-density ram will not work on some computers at all. If you have already inserted the ram and your computer does not boot up or goes beep beep beep. You have either inserted the wrong kind of RAM or your bios is not up to date enough to support the larger ram that you put in there. If that is the case take the ram out put the old ram back in and update the BIOS first. Verify that you are not trying to use high-density ram in a motherboard designed for low-density ram. Low-density ram will work with anything.

But high density ram will only work with certain computers.

nothing

if you have repalce the ram sticks properly and of the correct type , the computer will see them on start up

Yes and NO, there is nothing to download or do, but there are tests you should run on your PC to ensure the RAM is stable. RAM is a hardware level part that's taken care of by the BIOS, so it wouldn't be a bad idea to reset the BIOS, but this is not required.

It wouldn't be a bad idea to test the RAM for stability with programs like Prime95 Blend, Aida64, and Windows memory diagnostic tool. Memtest86 used to be the go-to test for checking RAM but Passmark bought the rights to Memtest and now they charge money for the version that will test for more than 1 round. Memory/RAM tests need to run for several to 24 hours.

Prime95 will also put a heavy load on the CPU as well, which will require a functioning CPU cooler. If the CPU does get too hot, make sure to turn off the AVX2, and AVX tests.