About 2 Weeks Since My First Attempt At Growing An Indoor Tomato Plant From Scratch, Any Tips?

I've been attempting to grow this tomato plant from scratch, this is the only survivor from the 4 cups I made.

I've been watering it once every 2 days and I don't know what to do for it

I also haven't gardened inside like this, it's my first time.

This south facing window is the best spot for light the soil is strained fresh from our outdoor garden and I hope what I'm doing so far is sufficient.

I'm wondering what to do next because I don't know when to plant it in the gallon ice cream tub for it to sprawl out. (Picture 2)

I'm growing it inside for 3 reasons.

1: we're in Colorado so it gets cold and our immaculate outdoor ones are short for the world

2: I want fresh tomatoes fresh from home just a walk to the back room

3: My Grandma from Illinois (Small Town Farmer Girl) broke her hip out in the garden and well I figured I'd bring the garden to her.

So I'm here asking for tips. I'll answer more in comments but I'm not sure what I'm doing. I started this out of bordem haha