SKETCH ORIENTATION: Go to SKETCH Tab > Set-up > Section Orientation > Set Horizontal Reference | Set Vertical Reference | Restore Section Orientation | Flip Section Orientation | Flip Sketch Plane.
NORMAL TO SCREEN: You can work sketching in normal view by SKETCH Tab > Sketch View.
DIMENSIONS: You can turn displaying dimensions On or Off by going to SKETCH Tab > Setup > Display > Dimensions | Constraint | Vertices | Grid.
Next, MODEL > DATUM > CURVE > Curve Through Points, select the reference points and choose between straight-lines or spline.
To create 3D sketches or 3D lines you can use Point features and then create lines between them: first go to MODEL > DATUMS > POINT, place the points where needed.
To finish the geometry just click the Middle Mouse Button (MMB) and basic dimensions will appear, which you can always change by clicking on them.
Next, create circles, boxes, and lines.
Next, the Sketch Tab will appear, here you'll find tools not only to Sketch but also to Constrain, Edit and Dimension your geometry.
Next, select the Sketch button > the Sketch Window appear > pick a Plane on the screen or the tree > click the Sketch button which is equivalent to OK.
The default datums will appear along with the MODEL Tab that contain the tools needed to sketch and extrude the part. Create a 2D Sketch: File > New > in the dialog box > Type: Part, Sub-type: Solid, Name: enter a name > OK.