Open your sheet metal template, then Sheet metal Defaults:

Click on the Pencil icon next to sheet metal rule to edit the rules. Select a rule on the left to start from Right Click > New Style > Give a name that you can Identify what it is. On the right Side define what you need such as: What Material to be used, what thickness, what Unfold rules to use (your K-factor, bend table, etc). Then save and close.
Now save these to your styles manager by going to Manage tab > Styles and Standards Panel > and click the Save Button.

This will save these styles to the styles library. This will only work if the project file's "Use style Library" is set to read-write. To check this, File > Manage > Projects and click your project file to see the options below:

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