My personal experience has proved it to me over and over again. Time management is a lot of baloney
. It doesn’t work. EVER. PERIOD.
From the dawn of civilization, it has never been about time management
. It has always been about priority management
.
Get your priorities straight and you will cut off a lot of things that are not as important. Give most of your time to the priorities that matter the most. 
Now to answer some of your specific questions
I’m really curious how you guys are managing this besides family, job, etc.
It’s simple. I’ve cut down pointless socializing. A lot of people think that cutting people off is bad. It is, in a way, sure. But that also doesn’t mean you have to keep sucking up to them all the time. I meet my non programming/different purpose friends on weekends. That’s strict. But very dramatically useful
Where and when do you study?
There is no fix time for my studies. I study on any/all opportunities I get. When I’m not doing something productive, (example walking somewhere, driving) I always have some computer science theory lectures playing on my phone. There are tons of usefull youtube videos as well.
My best friend there days is http://repl.it where I keep flirting with syntax etc.
On a weekly basis, how many time slots are there available for you to use?
This, as explained before, is not planned
. No time is a bad time.
Any really effective time management skills / tools you’d like to share with me?
Yes. Forget managing time. Manage your priorities.
Your daughter has to be your top most priority (Did I forget to congratulate you in the beginning?
Congratulations.).
Although you’re free to decide other priorities over this (I didn’t want to say such obvious thing but now I’m concerned that some gender equality nut job may get offended and frame me for enforcing gender roles on people - hope you understand what I’m saying here)
Then it’s upto you as to what and how should you prioritise your learning.
I’m sure, once you have some genuine clarity over priorities, you will have no issues managing time.
-All the Best.