When you recieve the invitation to join the campaign, the DM will likely be there to assist with importing and setting up characters. While we do use a custom sheet (in PDF format), Roll20 does automatic calculations on things like damage and buffs at a click of a button when you use the inbuilt character system. This is why we will be using both a custom sheet to track custom stats and roll20s inbuilt character sheet for macros at the same time. If you create your own token, please use the standard Roll20 Border featured in the above video.
In BnD, we use Roll20 for our gameboard and Discord for Voice Chat. Currently there will be a standard 5e Character sheet available in the Journal in the Roll 20 Client. This will assist with macros and general ease of access. However the custom character sheet does have important custom features on it, and will be required to be open and used during the game.
A more in depth guide to macros.