Which part are you not sure about?The +0.21% and +0.30% are...

Which part are you not sure about?
The +0.21% and +0.30% are cutoff grades for the resource, so any block model blocks that are below that cut-off grade are not counted in the total resource. This is to roughly account for the metal that will end up in the waste dump because it's too low grade.
The CuEq or Copper Equivalent is a tidier way of reporting the value of the copper plus the gold and the other valuable metals that exist in each block. There'll be a formula somewhere that explains how it's calculated.
The cutoff grades are different for open put and underground because the economics of the two mining techniques are different. Open pit is cheaper, so you can afford to mine lower grade material and still make it economic. Underground is slightly higher. That doesn't mean that all of that ore is economic to mine - that'll come later with the Reserves, not the Resources.