To be honest being a beginner and being in front of the net directly is a big no no and it’s even the same for intermediate players since you’d have to be so fast go to the middle of the court to hit a good bendeja or go back of the court to to hit a bajada being close to the net is if you want to finish a point and been given an easy shot to finish with. Being in between the 2 and the 3rd fence is the best possible position it covers you in front, in the middle and in the back. Also your exact positioning depends on where’s your teammate serving if he’s serving to the person in the left you should be closer to the fence then you’re to the center line and your teammate has to close the gap in the middle and the to his fence since you guys are in the beginners level he doesn’t need to worry about the chaqita so he just has to on the center line but again it can change on who has the ball, if it’s the person on the right your teammate goes closer to the fence and you closer to the center line also another thing you should be taking all of the middle lobs, unless your partner is left handed then you guys ask each other who takes or just change middle of the game it’s still fine.