fall apart = to lose control; to break; to fail.

His life started to fall apart when he began to drink again.

As a result, everything fell apart at his job, too, so he was fired.

 figure out = to learn how to do something; think for oneself.

The boys didn’t know how to make a cake, but they figured out for themselves how to do it.

They figured it out.

 fill in = to write information on a form; to talk and provide information. Fill me in.

She has to fill in the blanks on these forms.

 find out = to get information from another person, a computer, a newspaper, etc.

To find out what kinds of jobs are available, you can go online and do a search.

 for good = forever; something will or will not change.

He’s moving into a new house, but he probably won’t stay for good.