The previous poster has provided a good thread and you should also run a search within the
Disneyland forum for "first time," "what to do," "different rides," or similar. There's some variation of this same question asked multiple times every single week (i.e. WDW vet first time visiting DL).
My top piece of advice is to consider getting park hoppers. It's very different than WDW and the parks at DLR are basically one big park a few steps away from each other. DCA has a lot fewer rides than DL and is not a full day park in my opinion. DL has more rides than you can possibly do in one day. My personal opinion is that I would never do DLR without a park hopper and I do not find a DCA day to be satisfying without ALSO visiting DL at some point (whereas I could spend a whole day at DL and not visit DCA). DCA is a great park, but there's far less attractions than at DL.
I would not recommend automatically skipping rides of the same name from WDW. Pirates is far better and far longer at DL than MK. If Haunted Mansion is open when you visit (which it might not be) then yes, ride it. It will most likely be the holiday version which is very different than MK and themed to the Nightmare Before Christmas. Small World is also quite different than the MK version. Big Thunder has different effects on the last lift hill that are not present on the MK version. Space Mountain has different seating and music very different from the MK version.
In terms of ones that are very similar or identical to WDW: Runaway Railway, Rise of the Resistance, Smuggler's Run, Star Tours, Toy Story Mania, Soarin, Buzz Lightyear (some minor differences), Little Mermaid.
Unique to DL: Matterhorn, Nemo Subs (some similarities to the Seas at Epcot), Alice in Wonderland, Storybook Canal Boats, Casey Jr. Train, Pinocchio, Snow White, Mr. Toad, Peter Pan (many differences from MK), Indiana Jones, Guardians of the Galaxy, Monsters Inc., Incredicoaster, Radiator Springs, Luigi's, Webslingers, Grizzly Run.
This is not an exhaustive list. Look through these boards, the DL website, and look up videos online. Note that Radiator Springs and Rise are not on regular
Genie+, only ILL so you will have to plan to pay extra if you want to ride those and skip the lines.
Have a great trip!