Encoding card. Python's standard library encoded these strings while the card was written.
 Nothing below is an observed CyberChef result.

Alphabets, reused from Stage 04
Hex digits are 0-9 and a-f.
Standard Base64 uses A-Z, a-z, 0-9, +, /, and = for padding.

Worked input
NmU2Zjc0NjU=
Outer layer: Base64 of the hex text 6e6f7465
Those hex digits are the ASCII bytes of: note
Recipe order for this input: From Base64, then From Hex
Predicted output: note

Activity input
6c616e65
The characters are hex digits, and the length is even.
One operation: From Hex
Predicted output: lane
ASCII map for the activity: 6c=l, 61=a, 6e=n, 65=e.
Use the map to check your one-layer prediction.

Field input
NjQ2NTczNmI=
This string is Base64 of hex text.
It contains = and letters outside the hex digits.