i thought porte means wear ..
Why can't "tu apportes du pain" work here?
tu apportes du pain = you bring (in) bread
Tu prend... porquoi pas?
tu prends = you take/grab/get hold of
oui, prends, t'ai raison!
Doesn't "tenir" also work for carrying things?
Yes, you can use "tenir" here because it implies that the thing is held in your hands/arms.
Why not "Tu porte..."?
"You carry" can be translated in familiar "tu" or polite "vous" or plural "vous".
If you choose "tu", the verb has to be conjugated with the usual -s ending: tu portes.
with "vous", polite or plural, the verbal form is "vous portez"
Seriously, change things so that you know if it's supposed to be formal or not