When a design opens, the panel template fills the window from the left edge to the column on the right. Everything on it, template and instruments, is drawn to the same scale, and it stays that way when you change the size of your browser window.
Zoom in for finer placement. Use the magnifiers in the menu bar, beside CAD, Cut, Paint & Label: the minus zooms out and the plus zooms in, in 10% steps, from 50% to 400%. Or hold Ctrl (Windows) or Command (Mac) and roll the mouse wheel over the panel; the panel zooms around the point under the cursor.
Fit it back to the window. Click the percentage between the two magnifiers.
Most templates in the library are drawings, redrawn from their pictures, so their edges, openings and lines stay sharp at any zoom; a few made from photographs keep their pictures. Most instruments are drawings too: flight instruments, engine monitors, radios, displays, switches, breakers, knobs, jacks and vents.
Scroll. When the panel is bigger than the window, or an instrument or a placard hangs past an edge of the panel, drag the scroll bars or roll the wheel to move around it. The canvas scrolls past every edge of the panel, the top and left edges too. The column on the right stays where it is, and the panel scrolls under its edge; it never covers the column.
Zoom changes only what you see. An instrument's position and size on the panel are the same at every zoom, and so is what is saved and what is exported.
An instrument outside the view. If an instrument has ended up far off the panel, a line under the tool row says how many are outside the view. Press Bring them back and they are set in a row just below the panel, at the left; one Undo puts them back where they were. A locked instrument stays where it is until it is unlocked. The × hides the line until the design is opened again.