Filing with my spouse, net income.

I am currently filing my taxes, because I have a spouse now, it asks me to enter her information. When I get to the second page it asks "Net income from "spouses" 2021 federal tax return (Line 23600)...how can I have that information when neither of us have filed our 2021 returns because we are doing so now. We each only have our T4's. So how can I answer that question and proceed with filing my taxes and including her information when neither of us have filed so far. 

 

And im still so confused if we still file separately and include each others information or we have to file one tax return together. Everywhere ive read says we each file our own tax returns. Then im reading on turbo tax help "When you are married and living together, you can only file a tax return as either Married Filing Jointly or Married Filing Separately.  You would want to file as MFJ even if one spouse has little or no income." How do I know which way to file? Are there benefits or downfalls to one or the other? She earns a bit less than me and for 2.5 months in 2021 she did not work.