I suggest you look at the Lighthouse catalogue. Whether you go for this brand or a cheaper one, they all follow the same principles.
Numis and Optima are pretty much the same thing, I think the Optima is a bit bigger so it's capable of taking slightly bigger sheets. You buy the sheets separately so you can choose which pages suit you better.
In the 'classic' type of sheet, the coins go into strips of pockets that slide in the pages' bays. it's great because you can always get the coins out and re-arrange them again and again. The bad thing is that the level of protection is not great, and the pages have quite set sizes so you can't mix big and small coins in the same page.
The other system is put the coins in 2x2 carboard flips and then place these in special pages K50. The advantage of this is that the coins are permanently protected from the atmosphere and fingerprints, You can also arrange coins of different sizes in the same page. The bad thing is that once you put a coin in a carboard flip, you can't take it out unless you break it.
All my low value collection is in Numis albums with K50 pages, therefore in 2x2 flips. Better coins demand fancier solutions - Quadrum capsules in Volterra box for instance.