A conjunction is a word used to connect other words, phrases and clauses together.

The meaning of 'And' are also, in addition to. “And” is used when the statements are similar.
Example -
1. He’s 10 and she’s 12.
2. My mom and dad are teachers.

The meaning of 'But' are however, despite this. “But” is used to connect two opposite ideas.
Example -
1.I love ice cream, but he loves apples.
2. It’s sunny and hot, but I like it.