To dip your toes into the GWAS system, you are best off trying the smallest game in the series, CRUISER WARFARE
. Now, I must warn you, the operational system in the game is unique and unlike anything else in the series. But the tactical system is the same--and if you are going to love GWAS or hate it, it will be because of the tactical system and not much else. So this is a good way to start.
The topic covers the German "cruiser wars" in the early months of the First World War and is a very much cat and mouse affair at the strategic/operational level, thus creating a good bit of tension and fun in the game. Tactical actions can be tense or lopsided, depending on who is able to ambush whom. But you'll learn the system and know whether you want to keep going.
If you do, you'll want to move into either JUTLAND
or GREAT WAR AT SEA: MEDITERRANEAN
. Try one of those to get the full "operational" system used in the rest of the series. And marvel at all those ships
and scenarios! You won't get tired of playing them!