Eldritch Blast Code + Crit Question

Good Day everyone.  I have written a piece of code for an Eldritch Blast for DnD 5e. The code works pre-level 5 when it gets multiple beams, but while i was testing it, I rolled a Nat20 and realised I did not code in for the fact that it can crit and deal an additional 1d10 damage. can someone perhaps assist with the missing piece of code on it? ive been playing around with trying to make it crit for ages and i just cant seem to get it to work. thanks in advance! &{template:default} {{name=Eldritch Blast}} {{Target=@{target|First Target|token_name}}} {{Spell Attack Roll=[[1d20+@{selected|charisma_mod}+@{selected|pb}]]}} {{Damage=[[1d10]]}} /fx beam-smoke @{selected|token_id} @{target|First Target|token_id}

The standard way to handle this is by rolling the attack twice and rolling the damage twice.  You then choose the left roll (normal), high roll (advantage), low roll (disadvantage) for the attack, and if the one you chose is a critical, you add the right damage value to the left, otherwise just use the left.: &{template:default} {{name=Eldritch Blast}} {{Target=@{target|First Target|token_name}}} {{Spell Attack Roll=[[1d20+@{selected|charisma_mod}+@{selected|pb}]] | [[1d20+@{selected|charisma_mod}+@{selected|pb}]]}} {{Damage=[[1d10]] + [[1d10]] (Crit) }}

thank you very much Aaron, ill give it a try!