MS Excel - Nested If/And Statement

I'm trying to create a nested If/And statement to categorise academic students into focus groups.

The conditions I have to meet are as follows:

1. BD="Yes" and AY is =>5 or
2. BD="Yes" and AY is =<5 or
3. BG="Yes" and BF="No" and AY is =>5 or
4. BF="Yes" and BG="No" and AY is =>5 or
5. BG="Yes" and BF="No" and AY is =<5 or
6. BF="Yes" and BG="No" and AY is =<5 or
7. X="D" and Y="D" and AY is =<4 or
8. any other result

I've tried a few different ways but can't sculpt anything into one statement, can anyone help?