Here's a link to some videos; the first one will show you exactly how to set up and effect. https://www.fantasygrounds.com/forum...-Videos-for-5E
You'll want to create an effect of ATK:1; SAVE: 1, <ability>,<ability>; SKILL: 1, <skillname>, <skillname> where ability is the name of the ability that the character has proficiency in and skillname is the skills that the character is proficient in. So it might look like ATK: 1; SAVE: 1;strength, charisma;SKILL: 1, athletics, deception, perception, religion