can you please help me with this algorithm?

can you please help me with this algorithm?

I do not know what to do with this help me please.
Consider the problem of adding two large positive integers, each at most
twnty(20) digits long. One solution is to store the integers in an array
where a single digit is placed in a single component of the array. for
example the number 1,418,436,029 can be stored as shown below:
/ / / / / 1 / 4 / 1 / 8 / 4 / 3 / 6 / 0 / 2 / 9
/........................................................................................................
0 1 2 ... 10 11 12 13 14 15 16 17 18 19
design an algorithm called addLong(int1,int2, sum) that will take two
positive integers stored in two separtate arrays, in Array1 and Array2 in
the manner described earlier, take their sum and store the result in a
third called sumArray. (in outline format)
can someone help me with this?