Question Upgrading Asus G11CD-K (desktop) RAM & SSD

[sohaieb]

Hello,
I want to upgrade my RAM from 16 GO to 32 GO, and setup an SSD with my existing HDD.
I used crucial scan software to get the list of all supported RAM & SSD for my Asus G11CD-K (desktop) and here is the link:
https://www.crucial.com/scanview/E23445F331D926C3
My questions are :

1. for RAM:
   1. Are results of Crucial sure and safe in point of view compatibility when detecting my hardware configuration ?
   2. If not then how can I be sure when I want to chose to upgrade my RAM to support my Motherboard & my CPU ?
   3. I want to know also :
      1. Should I respect the exact frequency of the supported RAM in the Motherboard & CPU specs, or I can use a higher or lower ones ?
      2. When I used Crucial, I found many detected RAM's wich have higher frequency comparing to my existing one, so this can damage my PC ?
      3. Wich has the priority : respecting the Motherboard RAM spec , CPU spec or both of them ?
2. For SSD:
   1. Is my motherboard (G11CD-K) supports to install SSD with an existing HDD together?
   2. If yes then how can I setup SSD without formating my HDD, because I want to use SSD only for caches & rendering?
   3. If not, then can I setup an SSD wich have a capacity more then the specified one of the Asus specification.

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For reference to my Asus Desktop G11CD-K specification (the K is for Kabylake version):
https://www.asus.com/Tower-PCs/G11CD/specifications/