Form 1040ES Questions

I became a Freelancer as of January of 2019 and wasn't aware that I had to make quarterly payments throughout the year. However, I have saved up a good amount of funds to hopefully cover any fees (if any).

 

I have the following questions for 1040 Estimated Tax form. I've completed Schedule C and am I'm trying to complete 1040 ES to figure out my dues and am stuck on the 4 lines below. 

 

Line 2a- Deduductions: Where Do I find this information? Are they in various sections of 1040? 

Line 7 - Credits is this on line 12a of 1040?

Line 10. Other Taxes? What taxes are these referencing and where on 1040 would I find these? 

Line 11 b - If I have 2 children and we claim the Child Credit ($2,000) plus the ATC do I enter only $2,000 or $4,000? 

 

Any help would be greatly appreciated. 

Thanks!