Enz

if I'm not misstaken there's a portal leading to the place where kyogre/ groundon is in aegir cave; it's on top of the waterfall where you see the umbral clash between the 2 girls

The combination of the gate is unique to each playthrough, you need to solve it by yourself (it's a lot of trial and error but its simple) U place 1 star randomly if it's shining on the right of where florina is that means it is at the right place you need to get both left and right shining to finish it. Hope this helps too, good luck with that !

So basically for the ruby one you need to activate the crystal which will occurs as rock climb spots spawning near you. Sometimes you'll need to push some strength boulders or to backtrack a little bit. Hope this helps !