Hi @RichLucas, you're on the right track. Kudos on your attempt in your first flow.
I would have (and have indeed) used the same combination of functions\expressions.
Source

Flow / Results

At a high level, each variable is tied to an expression. They are:
IC number - grabs anything between "Approval" and "Plywood" in subject
substring(triggerOutputs()?['body/subject'],add(lastIndexOf(triggerOutputs()?['body/subject'],'APPROVAL'),9),sub(lastIndexOf(triggerOutputs()?['body/subject'],' '),add(lastIndexOf(triggerOutputs()?['body/subject'],'APPROVAL'),9)))
Product - Grabs anything after the ICnumber(#IC79-0591) in subject
substring(triggerOutputs()?['body/subject'],lastIndexOf(triggerOutputs()?['body/subject'],' '),sub(Length(triggerOutputs()?['body/subject']),lastIndexOf(triggerOutputs()?['body/subject'],' ')))
User - Anything between 'approval by' and 'Job:' in the body
substring(triggerOutputs()?['body/bodyPreview'],add(indexOf(triggerOutputs()?['body/bodyPreview'],'approval by'),11),sub(indexOf(triggerOutputs()?['body/bodyPreview'],'Job:'),add(indexOf(triggerOutputs()?['body/bodyPreview'],'approval by'),11)))
Job - Grabs anything between 'Job:' and 'Order Date:' in the body
substring(triggerOutputs()?['body/bodyPreview'],add(indexOf(triggerOutputs()?['body/bodyPreview'],'Job:'),4),sub(indexOf(triggerOutputs()?['body/bodyPreview'],'Order Date:'),add(indexOf(triggerOutputs()?['body/bodyPreview'],'Job:'),4)))
Need By - Grabs anything between 'Order Date:' and 'EF Job Number:' in the body
substring(triggerOutputs()?['body/bodyPreview'],add(indexOf(triggerOutputs()?['body/bodyPreview'],'Need By:'),8),sub(indexOf(triggerOutputs()?['body/bodyPreview'],'EF Job Number:'),add(indexOf(triggerOutputs()?['body/bodyPreview'],'Need By:'),8)))
This was quick and very preliminary.The expressions may need tweaking and you can choose to use variables or not. It's up to you. Might be easier to use variables to help troubleshoot.
Hope this helps,
Aman
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