Rotate from the root. Or pull from the tip.

Pose an armature in Pose Mode as in Blender. First with FK, one rotation after another along the arm; then with an IK constraint and a pole target, so the leg follows its foot and the knee knows where to point.

STAGE

3D Viewport

Mesh Relationship Lines Axes

LMB select · MMB orbit · Shift MMB pan · Wheel zoom

LMBSelect a boneGMoveRRotateXYZAxisAltR / AltGClearShiftIAdd IKTabEdit / Pose ModeCtrlZUndo

SAME KEYS AS BLENDER

Shortcuts you can use here

Keys work while the mouse is over the workspace, just like Blender sends keys to the editor under the pointer.

LMB · ShiftLMB: Select a bone · add it to the selection (the last one is the active bone)
R: Rotate the selected bones. Then X, Y or Z for a global axis, pressed twice for the bone's own axis. Type a number for exact degrees. Click or Enter to confirm, Esc to cancel.
G: Move the selected bones that are free to move (controls and the Hips). Connected bones can only rotate.
AltR · AltG: Clear the rotation / location of the selected bones
ShiftI: Add IK to the active bone: To Active Bone (the other selected bone is the target) or Without Targets
A · AltA: Select all / none
MMB · ShiftMMB · Wheel: Orbit / pan / zoom the view (AltLMB also orbits)
Numpad 1 3 7 · Home: Front / right / top view · frame all
CtrlZ: Undo · CtrlShiftZ redo

BACK IN BLENDER

An FK arm and an IK leg

This lab shows a simplified Blender: a few bones, rigid pieces of mesh and one IK constraint. Selecting, rotating, moving and the IK options behave like Blender's.

Add an Armature, extrude the bones in Edit Mode (E) and name them. Bend the knee and the elbow slightly in Edit Mode so the IK knows which way to bend.
Switch to Pose Mode (Ctrl Tab). Rotate with R; R X X uses the bone's own axis. Alt R clears it.
Add control bones that do not deform: in the Bone properties turn off Deform, and clear their parent (Alt P) so they move freely.
Select the control, then Shift-click the Shin and press Shift I › To Active Bone. Set Chain Length to 2.
Set the Pole Target and fix the Pole Angle (often -90°) until the knee points at it.
Parent the foot to the IK control so it stays flat, and use the constraint's Influence for an IK/FK switch.