Zoom and scroll
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 at the right end of the tool row: 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.
Scroll. When the panel is bigger than the window, drag the scroll bars or roll the wheel to move around it. The column on the right stays where it is.
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.