Compost / Purity - How does it work?

Greetings,
Was wondering how Compost and Purity work ...
Is it just basically put in High Purity Crops / Plants, you get better Humus?
Is there any numbers / ratio on how many you have to put in the compost?
If I put in 10 High Purity stuff and 10 with nothing .. what happens?
Thanks
Was wondering how Compost and Purity work ...
Is it just basically put in High Purity Crops / Plants, you get better Humus?
Is there any numbers / ratio on how many you have to put in the compost?
If I put in 10 High Purity stuff and 10 with nothing .. what happens?
Thanks