Booming Blade Macro

I’m playing an Arcane Trickster Rogue, Booming blade is not in our compendium, so I need a macro. I have no idea how to write them lol. Does anyone have one they would mind sharing that scales appropriately with level. I would be deeply appreciative. PS the only macros I have set up are a sneak attack one I found on YouTube. So it adds a button to the dialogue box to click if sneak attack is applicable. I’d love the same thing to add on melee weapons so I can click for booming blade damage if applicable.

Any help please? Even if its an idea I'd appreciate it. 

A few things to keep in mind with questions like this: 1. Different character sheets have different roll templates built in, and possibly different naming of attributes, even within the same rule set if there are multiple sheets.  People need to know what character sheet you are using to give a useful answer. 2.  A lot of different games are played on Roll20.  I don't know what booming blade is or what it does, so I most likely am not playing the same game(s) you are.  Unless you post the mechanics of the ability you want to make a macro for, no one can help you unless they play the same game you are.  The more info you give about an ability, the easier it will be for someone to help you. 3. If you have made a start of building the macro, posting that can give people a reference point to start from.