Adjust the Quick Play filter again to keep the modes you like and try new ones. Continue to level up your Operator and your weapons, incorporating new unlocks into your Loadouts over time.
Start building out additional Loadouts after unlocking Custom Loadouts at Player Level 4. Adjust your Loadouts according to the upcoming map and mode.
Use the Firing Range in the Loadout menu to test different weapons and weapon settings. Once you start getting the hang of the Multiplayer experience, invite your friends or search for a group to join by selecting the Social tile in the top right menu.