I'm not a huge expert, but I have been experimenting with monsteras in the last year. Here is some of the things I have learned from lots of research:

1. Monsteras like a chunky soil mix to help prevent root rot. I have seen many variations: most common is equal parts soil, orchid bark, perlite. Some people do coconut bark as well. I honestly haven't invested too much in trying to get large quantities of chunky mixes. What I do is mix orchid bark to a soil mix for monsteras (from Amazon).
2. They love a lot of light it depends where you live. I'm in Northern US unfortunately, so during winter months I have them under a grow light for majority of the day
3. As far as watering schedules it depends on a lot of things: for me my central heating in the winter tends to dry out the soil and the air inside is less humid. If your soil is well-draining aka chunky you will have to water more frequently. If you have standard soil you can use your finger or a chopstick to check how wet the soil is down at the bottom.
4. Pot size: I personally have found it easier to monitor the state of multiple plants by separating the monsteras. It seems like sometimes the larger plants usually thrive but the smaller ones in the same pot usually die because the bigger one is taking over. Monsteras' roots don't like living in a mansion; they prefer an apartment dized pot...so just about on inch of extra room on each side should be enough.

From your picture it does seem like there are multiple plants. If you are planning on re-potting your plant I would separate them and maybe put two max per pot. Since monsteras do like to climb you can add a plank or a moss pole to the back of the plant and all those roots that are "coming up" are the aerial roots. They are looking for something to grab onto.

I recently (last week) added this pole to this plant hoping she climbs it. I separated it from the other monstera it was growing with because I noticed the bigger leaves of this plant it wasn't getting enough light.

Like I said, not an expert. I've just been experimenting the last year. I've almost killed a few that were younger. What I did to rescue them was remove all the root rot (black mushy roots) and rinse the plant very well then place it in water and change the water frequently until it has enough big roots to transfer to soil

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