Combine 2 external values of 2 arrays into another array's value


see pictures below the arrays are shown and their details .

i want to create an array of string type Called “NumLetts” and populate it with string elements : a1,b1,c1,d1…a2,b2,c2,d2 …a8,b8,c8…h8 . …

…populating them all by hand would be tedious , so what’s the best way to go about automating the process ,??

i thought maybe creating 2 separate arrays one being of integer type called “Numbers” ,the other being string type called “Letters” , and populate the first with the integers 0,1,2…6,7,8 then populate the second one with strings a,b,c,d…g,h .

the next step would be to criss-cross combining each element from the 2 arrays into a new array of strings which is array “NumLetts” forming elements like a1,b1 …g7…h8 . .and so ( how to do this i don’t know i mean combining 2 elements of 2 arrays into 1 element in a new array .)

Thank you .