Everything great takes time, coralline will come with time and stable take parameters.
You mentioned no live rock, so assuming you started all dry. That is not to worry though! As others have mentioned, if you got any snails with purple on their shells, that is coralline. Them being in your tank will allow it to spread to your rockwork, glass, etc. over time. Any frag plugs or coral pieces you grab from your LFS or other providers likely will also have coralline on them. Fish Fan also linked coralline in a bottle which I have heard does work as well!
In my case, I'm also a newbie! Started my first tank in August and we spun up a second 25 Gal in the fall. The tank I started in August was primarily dry rock with 8 lbs of TBS rock. The second tank was mainly TBS rock with a small amount of dry rock. We noticed coralline growth on the tank/powerheads of the 25 Gal tank before we saw it in the larger tank. Both have coralline, but live rock is (in my very limited experience) going to be the fastest way to get it happening in your tank.
In my research I found that the hard green algae comes before coaralline. I would say, in my very limited experience, that seems to run true. My dry rock in the SR60 was covered in hard green algae which seems to have gone away and is slowly being replaced my coralline. I will also say in my very limited experience that live rock, even a few pieces/some rubble from your LFS that have coralline already established are going to help in getting is growing in other places of your tank quicker.
Your parameters look fine from what you have provided, I'd also recommend tracking your phosphate as that is an important one to know as well! Calcium is also one to keep an eye on here as coralline will consume calcium and alkalinity. The most important part about your parameters is stability! Do not chase numbers, but maintaining stable, healthy ones is important.
A few months minimum to see growth, it took about 4-5 in my case on the SR60 to see noticeable patches of growth.