Hi
Try this....I do not have Topfield, but other types work like this.
You have 32 digit key.
Every set of keys is 2 sets of 16 digit keys.
So take the first 8 pairs of keys (16 digits)from your 32 digits. Enter in Topfield as 1 line of keys...key 00
Take the second 8 pairs of keys from your 32 digits and enter in Topfield as 1 line of keys...key 01
If you see spare lines for keys 02 and 03, copy your key 00 to key02, copy your key 01 to key03.
So your keys 00 and 02 are the same, and keys 01 and 03 are the same.
If you look at a Topfield user guide on web it will tell you exactly for that type of reciever.
Hope this helps.