"$1000 goes to capital stock. $69k goes to additional paid in capital.

is that how you’d account for it?"

You would have $20,000 bank asset and $50,000 Fixed/Other Asset as Debits. Then, $1,000 Capital Stock and $69,000 Paid In Capital as Equity Credits.

"if there is Ninother income and expenses, they will have negative retained earnings because the fixed asset depreciates but the $69k stays in additional paid in capital."

The Income & Expense activity is the (change of net assets from operations) for how this year ended (loss) and how the next year begins:

Bank $20,000

Fixed/Other Asset $50,000

Depreciation on Assets -$10,000 (example)

= $60,00 total "net" assets

And:

Stock $1,000 <== no change

Paid in Capital $69,000 <== no change

Retained Earnings -$10,000 <== loss

= $60,000 Equity, which is why the phrase "Net Assets" is also applicable here.

When there are liabilities, they reduce equity, because you owe something to others. When there are assets, they increase assets, because you own something of value.

If there was income above that depreciation expense, and it turned Net Income(loss) positive, that would be reported for taxes, and if not distributed, that is carried over as Retained (AAA).

That's why, in my class, I first show The Accounting Formula, then swap it to "common folk reckoning."

"I also understand that contributions don’t affect AAA. So on new corporations new contributions don’t pay any bearing on AAA, right?"

AAA is not Contributions. Remember my comment: It doesn't matter how you slice-and-dice it, Equity is Equity. Multiple equity accounts for tracking balances are for clarity.

For your first year of of operations, there is nothing "carried over."

I just reread your initial comments. You first stated the Liabilities are "The liabilities (mostly paid in capital) is staying the same." So, we seem not to be using the same understanding. Paid In Capital is not the same as Loaned. Liability = Borrowing and need to repay it.

Asset <== the Values for stuff we own, including money

Liability <== what needs to be Paid/Repaid

Equity <== the difference in the two above

Let's redo your math:

$20,000 bank asset

$50,000 Fixed/Other asset

= $70,000 Total asset

$69,000 Liab as Debt to Shareholder

+

$1,000 Stock issued

= $70,000 Equity

Second year:

$20,000 Bank

$50,000 Fixed/Other Asset

-$10,000 Asset depreciation

= $60,000 Total asset

$69,000 Debt to shareholder

$1,000 Stock

Net operating loss (going to RE) -$10,000

= $60,000 Equity

I hate working math in a scrolling window. I hope that all makes sense.