Not an expert on reading drawings by any means, but it looks to me as if the upper radius in your larger red oval is saying it’s 120mm radius, starts vertical, and extends down to where it meets the small 35mm radius whose centre is 19.5mm below the dashed reference line.
If you start from the top of this 120mm radius arc, you know its centre is horizontally 120m ‘left’ of the arc above it. And you know it is half of 16.5mm (i.e 8.25mm) left of the vertical centreline. So that fixes its centre as on a horizontal line 128.25mm left of the centreline. Draw part of that arc from centre, radius and angle (menu Draw/Arcs/Arc in latest two or three versions of SU).
Locate the centre of the 35mm arc from the dimensions given and draw that too, to meet the R120 arc. Erase any overlap.
Most of the rest you can draw starting from the top down, using an arc drawn roughly from known endpoint to endpoint with any small bulge, then changing the Radius in Entity info. Make the next arc tangent (shows cyan marker with default style settings).