Zweihander initiative macro

Hey gang,  I'm trying something new and joined in a Zweihander game starting this Thursday.  The GM says he usually manually adds the players to the turn order.  I see that there is no initiative button on the character sheet but there is an initiative attribute and field on the sheet.  Is there a way to make an ability that I can set as a token action to roll initiative and add myself to the turn tracker?  Thanks in advance for any help.  The attribute is @{initiative}.

Hello, I found the same problem last week when I was trying to start up a Zweihander Campaign, and the game did a complete stop, at the Roll Initiative part lol, anyway's I found this Macro: &{template:zweihander} {{name=Initiative}} {{character=@{selected|character_name} }} {{initiative:= **[[ 1d10+@{selected|initiative}-@{selected|initiative_overage}&{tracker} ]]** }}

Thanks!

I am trying to use that macro but I get an error that says  TypeError: Cannot read property 'substring' of undefined