Am I using artboards wrong? (Transparency and setting document size)

[Cobalt7 Imaging]

I design shirt graphics. My workflow today is I create a new document (not an artboard) that is 4500x5400. I create the design, then export this document as a transparent PNG. But what I *really* want is to have the 4500x5400 document on the screen, with a smaller 2500x2500 artboard to the side of my screen where I can place a reference drawing or graphic while I work in the larger document.

The issue with using artboards is I can't
1) figure out how to properly set their sizes (I don't see any way to set them to say, 3000x3000 without trying to drag them around to the size I want - basically guessing) 
2) how would I export an artboard as a transparent PNG? I didn't see a way to do this. I had to copy the design to a new 4500x5400 document, then export it as a transparent PNG. 

I guess ideally I would have an artboard to one side, and a main document to do my work in. Is this simply a limitation of artboards, or am I just an idiot (likely....). It seems like they're great for mockups and ideas, etc, but for final production work, they seem limiting. 

[Oufti]

1 hour ago, Cobalt7 Imaging said:

figure out how to properly set their sizes (I don't see any way to set them to say, 3000x3000 without trying to drag them around to the size I want - basically guessing) 

• Select your artboard in the Layers panel
• Set the dimensions in the Transform panel

1 hour ago, Cobalt7 Imaging said:

how would I export an artboard as a transparent PNG? I didn't see a way to do this. I had to copy the design to a new 4500x5400 document, then export it as a transparent PNG. 

You have to export your document from Designer (if needed, when in Publisher or Photo choose File > Edit in Designer):

• In Designer, chose the Export Persona
• In the Slices panel, select the artboard(s) you want to export (by clicking on the circle on their right)
• Select PNG: it will be automatically transparent if needed

 

You colud be interested by this tutorial:

 

[lacerto]

Obsolete.

[Cobalt7 Imaging]

@Oufti and @lacerto - thank you both very much! This is what I needed. I was missing the Transform panel for some reason, I knew there should be a way to specify dimensions! So thanks to both of you, this is very helpful and should get me headed down the right path. Appreciate you both!