To build an indifference curve we can first find the utility of a portfolio with 100% in the risk-free asset, then

change the standard deviation of the portfolio and find the expected return the investor would require to maintain the same utility level.

change the risk-free rate and find the utility level that results in the same standard deviation.

change the expected return of the portfolio and equate the utility to the standard deviation.

find another utility level with 0% risk.

find the utility of a portfolio with 0% in the risk-free asset.