Drop down attribute in roll macro

Hi guys. I'm generally new to roll20 and coding overall, so I thought someone can give me some help here :D Basically what I'm trying to create is a macro which has a drop down menu that asks the player to choose a custom created attribute (like the skill Atletics) and then roll a d20 with that attribute as a modifier. Been trying to research to see how macros work and I kinda know how to do basic things, but when it gets a little "advance" for me my brain hurts :D So I would appreciate if someone can help out ^.^

Example of creating a query; Say you create some custom skill attributes on the Attributes & Abilities tab(these attributes could also be created from a character sheet.  same concept); acrobatics-mod athletics-mod ... #Skill_Macro [[ 1d20 + [[?{Choose a skill|Athletics, @{selected|athletics-mod} |Acrobatics, @{selected|acrobatics-mod}} ]] ]]

Thank you sooo much dude! :D