Is there somewhere I can enter capital loss from a mutual fund for this tax year? or do you only enter capital gains?

Both capital gains and losses are reported in the same tax year that they occurred. 

You enter each sale and the sales price and your cost.  Turbo Tax calculates the gain or loss.

Enter a 1099 B under

Federal Taxes on left or Personal (Home & Business)

Wages & Income

Then scroll down to Investments and Savings

Then Stocks, Cryptocurrency, Mutual Funds, Bonds, Other (1099-B) - click Start

Then click Add Investments at the bottom

Next screen hit Continue

Then don't enter or pick a bank, at bottom click on Enter a Different Way

Then pick box Stocks, Bonds, Mutual Funds - then Continue

Enter the bank or broker

Answer some general questions and Continue

Then Continue a couple more screens and you finally get to the 1099B entry screen.

You can enter a 1099B manually or try to import it.  If you import it be sure to check it over close and make sure the cost basis got imported and is right.  How to import your 1099

https://ttlc.intuit.com/community/entering-importing/help/how-do-i-import-my-1099/00/26254

Oh and you need to upgrade to Premier to enter sales.