Interpreting Homoscedasticity and Residual spread for linear regression

I am new to Data analytics. I have difficulties of understanding what both the Homoscedasticity and residual histogram is trying to convey. Please any help is appreciated.

I have a linear regression checking for relationship between the age of shoppers and their rating of products (1-5). I am to check data assumptions for homoscedasticity and residual. i have the below graphs plotted with r after building the model.

Please what do these readings mean?