First things first, feel free to spread the ball about as much as you like in PES 2019. In fact, passing like the thing's a hot potato is encouraged, and it'll leave CPU opponents reeling. The same is true (to a lesser extent) of human rivals. Intricate sequences are the law in Konami's world.
Passing also helps you defend that 1-0 or 2-1 lead.
On the offensive, one-two passing is an excellent way to carve up defensive back lines, especially in one-player matches, and don't forget to make use of those through balls. PES is much more forgiving than FIFA with lofted long balls; there's no laser-guided system, so passes don't need to be bang on to end up working out.
If you're a fan of Barca's old Tiki-Taka approach, then you're in for a treat. Set up some Gegenpress tactics and knock it about in the middle of the park for a bit. You'll notice that CPU midfielders are thrown off by quick movement, and so are opposition strikers.