1-How can I verify if I did a multiple Regression (with dummy variables) correctly using Excel.

2-From there how can I analyze the coefficients and to determine how the variables are related?

3-How do I conduct a t-test with the information I get in excel? Do I need to use the t-statistic to calculate the t-test?

4-I know that the p-values in the regression are compared to the 0.05 significance level and if they are below this value they are significant to the regression.

I can give specifics on the problem I'm working on if needed.