keeping dimension equal without adding a relation

Hello,

I am new to Solidworks, so this is most likely a simple thing to answer...

When making a rectangle and using the smart dimension feature i try to change the dimension of say the top line and it changes only the top line making the rectangle no longer a rectangle. When watching tutorials everyone elses changes both top and bottom dimension so they are equal. Heres a photo of what im talking about.

and if i try to make the other side the same dimension which i feel should not need to be done it creates what is in the 2nd picture

Thank you for any help and guidance,

SolidworksEducator Student