I'm new to maps and making homebrew monsters. I was following a guide online for making attacks be rollable on maps and typed this as an example:

Claw. Melee Weapon Attack: [_rollable] +9;{"diceNotation":"1d20+9","rollType":"to hit","rollAction":"Claw"} [_/rollable] to hit, reach 5ft., one target. Hit: 13 [_rollable](2d8+4);{"diceNotation":"2d8+4","rollType":"damage","rollAction":"Claw","rollDamageType":"slashing"}[_/rollable] slashing damage.

With this, the roll to hit shows up as rollable, but the damage does not. Could anyone give any help diagnosing what went wrong, as well as a link to a better guide for these things if one exists? (adding underscore to reveal code)

Can you paste the action without the codes, so I can run it through the tool and see if it was coded properly? 

Claw. Melee Weapon Attack: +9 to hit, reach 5ft., one target. Hit: 13 (2d8+4) slashing damage.

Thank you for any assistance can provide.

Thank you. I used the tool for that on a homebrew monster and got it working fine. Here's an unlisted video I made to show the steps I took.

Thank you! I honestly didn’t know that tool was there to translate it into the dice rolling code for you, was trying to freehand it all.

Quote from RamseyRed >>

Thank you! I honestly didn’t know that tool was there to translate it into the dice rolling code for you, was trying to freehand it all.

 
Glad it helped! 😊

Here's a fun one for you, Cyb3rM1nd...the dice roller for damage WORKS in encounters just fine, but not in maps...

Claw. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 20 (3d10+4) bludgeoning damage, and the target is grappled (escape DC 15). The crab has two claws, each of which can grapple only one target.

Dice block generator turned it into this:

Claw. Melee Attack Roll: [ rollable]+7;{" diceNotation":"1d20+7", "rollType":"to hit", "rollAction":"Claw"}[ /rollable] to hit, reach 10 ft., one target. Hit: 20 [r ollable](3d10+4);{"diceNotation":"3d10+4", "rollType":"damage", "rollAction":"Claw", "rollDamageType":"bludgeoning"}[ /rollable] bludgeoning damage, and the target is [condit ion]grappled[/cond ition] (escape DC 15). The crab has two claws, each of which can grapple only one target.

Works in encounters all day long, won't work in maps.

Figured it out!!! You have to take the parenthesis off the first 3d10+4, it fuggles with the code.

Claw. Melee Attack Roll: [ rollable]+7;{" diceNotation":"1d20+7", "rollType":"to hit", "rollAction":"Claw"}[ /rollable] to hit, reach 10 ft., one target. Hit: 20 [r ollable]3d10+4;{"diceNotation":"3d10+4", "rollType":"damage", "rollAction":"Claw", "rollDamageType":"bludgeoning"}[ /rollable] bludgeoning damage, and the target is [condit ion]grappled[/cond ition] (escape DC 15). The crab has two claws, each of which can grapple only one target.

THAT code worked fine!