During the beta, the only way to buy weapons and accessories and to edit your loadout is during a game.
While you are on the respawn screen, you can select a class loadout, then you can use your controls to move inside that loadout and select things like your main weapon, side arm, grenades, tools, etc..
Then you press the correct button * to access the sub menu, inside this menu you will find new items you can purchase with your war bonds and you can also select purchased items to spawn with.
The same way applies for vehicles, which is annoying because this means you have to wait for vehicles to be available to be able to customize your loadout.
When i say the correct button, you should find that on the lower left side of your screen, i see you are playing on PC, i personally play on
xbox 1 where the correct button is Y.
There are lot of similarities with Rush. Like in rush, the attackers are given a limited number of reinforcement tickets. In Operations by default it's 250 for 64 players, 200 for 40 players (150 for both prior to the fall update). When an attacker dies, a ticket is lost. When Medics revive a teammate, a ticket is refunded.
When tickets are at zero, game continues as long as there isn't a flag fully in defenders possession (so for example either both are disputed or one is taken by attackers, other is disputed).
Unlike Rush however, in Operations advancing to next set of objectives does not fully reset the ticket count, instead you get additional 50 tickets (30 prior to patch). There is however an opportunity to gain some additional tickets. Retreating defenders are marked and killing each of them grants attackers 3 tickets (2 prior to the fall update)
Best Answer
Unfortunately, you can't unlock any weapons by playing the campaign. You can, however, unlock some skins.
Source - no weapons
Source - skins