1. I will start with its left leg, for the leg joints, I turn off some joints axes Degree of Freedom. To do this, select a joint and open its Attribute Editor window (Ctrl-A). Do this to the joint that you think has only one or two rotate axes.
2. Then, I will proceed to create IK. Select the IK tool: skeleton -> IK handle tool or select from the shelf.
From the IK Handle tool option, switch the Current Solver to ikSCsolver.
3. With the tool still selected, I clicked on the left leg's joints that I wish to apply with IK.
4. You will find an IK handle node in your hypergraph. Rename it. Press Y to return to previous tool, then I create IK handles for both of the toes. There are total 3 IK handles I created for left leg.
You can start move around with the IK handles to see how IK works with your bone. Undo the translation to get it back to position before moved. O.K, now select the pelvis joint, translate it, you may find that the left foot was moved with it. We would like it to stay on the ground. To do this, we need to add locators to control it.
5.Create a locator and holds down V key to activate point snapping, then MMB drag the locator to heel joint. Then create another 2 locator, using the same way to place it to locations of toe1 and toe 2. Rename the locators. Then parent the locator to its IK Handle.
Now I will select the pelvis to move around, the left foot be stay on the ground.
6.Using the same method to apply IK to right leg.