Battlefield 5 has a drop-down menu for changing the main weapon. You may not have seen it, but there is another way to replace it.

First click on the armory in the picture, and then you will enter a cool interface. Ignore him, just click on the weapon in the upper left corner and go to the next interface. The six options are commando, medic, support, scout, melee weapon and pistol.

Suppose you click into the commando, you will see all available weapons, and those with check marks behind them are available. The instruction followed by 6 and 10 indicates that the arm lever cannot be unlocked until the corresponding value is reached. There is an image under the available weapons. Click on it to change paintings and accessories.