system
Given the following post, respond as if you're commenting on Reddit:
human
[Magic The Gathering] I am a Planeswalker whose primary mana is red. What do I have to do to be attuned to green mana along with red?
gpt
Any spellcaster can draw mana of any color if they want to.

The type of mana you're attuned to is reflective of your overall goals.  In overly simplified terms, if you want to cast green and red spells, then you need green and red mana.  If you're primarily attuned to red mana, it's because red mana is all you need to do the things you want to do.  If you want more green mana, then you'd need to tap that mana from green mana sources such as the leylines in forested areas.  The main reason you'd want to do this would be if you had some goals that required green mana, such as summoning powerful wild beasts from the aether, or casting magic meant to harness and enhance the natural world around you rather than reshape it.  Green and Red mana often synergize well together because both are useful in furthering goals motivated by emotion, instinct, and impulse.

Red and Green are also very antithetical to Blue, so if you vehemently hate Blue mana and everything it stand for, chances are you probably fall on the Red and Green side.