Hey Holly!

Philodendrons are incredibly hearty house plants. You can nearly kill them and nurse them right back to health. Looks to me like your leaves are browning and curling under--a sign your plant is getting too much light. Try putting it in front of a window that gets only morning light and see if that helps!

It could be the plant got a bit cold as the leaves were unfurling.

How should I water it? Wait till the soil all dries out?

Marcy, new leaves typically curl out from the center, a bit like a hot dog bun opening. These look more like sick leaves to me.

Holly, the top inch or so of soil should dry out between waterings. Stick a finger into the soil, about as deep as your top knuckle. If it feels dry that deep, time to water. The soil should be evenly moistened when watered. They need a bit less water during the winter months when growth slows. Newly potted philodendrons need to be carefully watered during the first month to make sure their roots don't dry out completely.

One more question: when i do water it, how much should i pour? until water leaks out from the bottom,or is that too much?

Pour until it comes out the bottom and then some. Make sure you remove all the acess so it does not sit in it.

It's important to do this to flush out the soil of salts and minerals and also to make sure the whole root zone is getting watered.

It also looked like new growth to me. As it seems to be only affecting the newest leaves and not the others.

Agree with Mr. Blubs--top leaf looks like a new one, based on shine. My newly potted philodendrons did some leaf wrinkling once. I was trying to be conservative on the water as I am terrified of overwatering anything. In my time with heartleaf philodendrons, I have observed that they do need more consistently moist soil than some other tropical plants (but not soggy, by any means).

While some other tropical plants can go dry to the bottom of the pot (like the pothos), with the heartleaf philo, measure soil dampness like Meag described. I think your plant will be fine. Though they can start to look a bit rough if neglected, these are very hard to kill plants.

Marcy, new leaves typically curl out from the center, a bit like a hot dog bun opening. These look more like sick leaves to me.

I realize that, but the top photo looked like a new, shiny leaf unfurling to me.