new audi a4 estate avant 2016 plate help

[audia4cardad]

i bought  a new audi avant a4 estate 2016 plate 2.0 tdi from a used car shop and i just wondered what do u press to get hot air out of all the fans just i went on youtube and did change the fan to top setting how i saw..but it doesnt seem to come out of the middle vents below the screen/above the a/c dials and out of the left and right its blowing warm/cold but it feels like not with much power? could it possibly need a air con re-charge? have contacted where i bought it from but no response yet...wondering if its just me :s