Hi Skybreck and welcome!
You can set the tab indexes for the fields to make sure that the field you ant to set is where the form opens. Right click, go to properties and click on Display. Set the tab index to 1.
You can programmatically do this with qRules SetFocus command but that requires a plugin and sandbox. We can help you there if you want to go that route.
But, the tab index technique is the simplest. Big stick though.
:)