Multiplayer - Ladder Games - Pro Cycling Manager 2017 - Official Guide
Multiplayer - Ladder Games
The left side of the main screen in multiplayer mode is for ladder games. To take part in a ladder game, just tick the "One-off Race" and/or "Track" boxes if you want to look for a game in either of these modes.

Note: the search can take several minutes depending on the number of players looking for races.