Think of it this way...
You're a teacher standing in front of your students and you have a lot of info to pass to them on the backboard, is a large black board better than a small blackboard that you would need to erase and write the following parts? Of course the larger board would be better! Thats RAM, the blackboard in your computer.
Now lets look at storage...
Hard Drives (HDD) use a spinning disk to record like a tape recorder the information to be called on later. Like a journal you write your travels in, so later you can tell people the places you visited.
But, paper journals are awkward and slow thumbing though the pages. So a faster system was created called Solid State Drives (SSD). Here we can think of it like a rolodex spinning to the needed card in a snap. But, this technology is costly! So some smart folks came out with a new kind of hard drive which also has SSD technology added to it, unlike the larger SSD drives, here we use a smaller SSD for caching, but, use a larger traditional HDD for the long term storage. So we gain the benefits of both technologies! Gaining the zip of the SSD and the deeper storage of HDD in a single device this is called a hybrid drive or SSHD.
So where does that leave us two distinct areas memory & storage which depending on what you are doing likely need to be increased. Today 4 or 8 GB of RAM is really needed for must things and 256 GB to 1 TB would be needed for storage.
Does that help explain things?