It depends on the type of data you are storing in the array.
But let’s say you store 4-byte values.
Then the first value can be stored at indices 0-3, the second value at indices 4-7, …
TEAL has operations to extract substrings easily: Byte Operators — PyTeal documentation
If you need an array of uint, you can first convert uint into 8-byte strings usinghttps://pyteal.readthedocs.io/en/latest/data_type.html#conversion