1 dummy bot will be added to the game, this bot will progress the objective for you so you can practise other points. Put yourself on Team 2 if you want to practise attack.
Press F (Interact) to teleport the bot to the objective and press it again to remove him from the objective.
Press Crouch to respawn yourself to reset your rollout. The timer will also reset so you can find the best route back to the objective.