Like how mermaids would experience and perceive life underwater. Want something grittier then the inconsequential, and uninspired in my opinion, way the Aquaman movie portrayed an entirely underwater civilization. Particularly trying to describe sight, sense of self and surrounding areas. I've been searching for quite a while, and the only book I've found that may be helpful is The Silent World By Jacques Cousteau.
I'd say the first thing to be concerned about for an underwater civilization is accessibility fire. Fire is the cornerstone of all civilization, and without a consistent source of heat to gather around, cook with, light the darkness with, and use to stave off the cold seasons civilization likely won't get far much at all.
Here's a link to a very similar post for you to reference with very detailed answers:
What the underwater lacks:
fire - maybe not needed as a way to prepare food, but one of the first simple thing in the zone of proximal development of an incipient civilization. You will need to find a similarly simple thing to control and which brings immediate (even if low level) benefits
metallurgy will come very late in the development, probably after electricity (and maybe as a result of it). As a note, availability of metals may come early than for humans, under the form of metallic nodules on the seabed
electricity may come very early (think electrical eels) but electrostatics very late. I believe magnetism and the relation with the electrical currents may be the replacement for fire and subsequently metallurgy. (just use some protein mucus to insulate those wires).
some chemistry will also come late, especially whatever implies gaseous reactants and/or reaction medium. Aqueous chemistry can come much early - an aquatic species will have the taste sense much more developed than terrestrial beings, they won't even need litmus to discern between acid/base.
the thing that will be missing on the path to civilization: astronomy and cosmology.
Hmmm... hey, look, from the last two points, how about you consider an amphibian species? It would be the best of two worlds (probably so good condition an amphibian species may never be pushed towards evolving intelligence, but maybe one can handwave something in)