I am Canadian,sold a rental condo in Florida in 2018. For capital gain, how can I calculate the tax amount due to capital gain and which line it goes to?

am Canadian and sold a rental condo in Florida in 2018. For capital gain, is it taxed at different rate than rental income? How can I calculate the tax amount due to capital gain and which Line I put it in?  I put the total capital gain and rental income into line 41 and 42 and can’t figure out how the rental income and capital gain are taxed differently.

Every year, I have rental income loss incurred after claiming full Depreciation, how can I use these rental income loss to reduce the deprecation recaptured amount?

With Depreciation recapture, should I use the full amount as per IRS, or should I use the amount as per I filed my tax every year, as I used the Alternative depreciation approach (40 years amortization). 

Can I efile form 1040NR?