$p$ value is the probability of finding the observed $F$ value or larger, given that the null hypothesis is true.
 Find the column with the correct number of degrees of freedom in the numerator. This is the degrees of freedom corresponding to the numerator in the formula for the $F$ value (e.g., df model, df between, df regression, etc.)
 Find the rows with the correct number of degrees of freedom in the denominator. This is the degrees of freedom corresponding to the denominator in the formula for the $F$ value (e.g., df error, df within, df residual, etc.)
 You now have five options for $F$, each corresponding to a different upper tail probability (which you can find in the column named "$p$" or "$\alpha$"). Find the two $F$ values that enclose the $F$ value that you found, and check what their corresponding upper tail probabilities are. The $p$ value corresponding to your $F$ value is between these two values
