The basic idea is to start with a cube divided into a small number of slices in each axis, forming a connected group of small cubes.  You then move vertices around to reshape the cubes, and extrude more cubes, until you've built a very simple block figure that approximates the shape that you want to model.  Then using surface subdivision and smoothing you can create smooth surfaces that follow almost any basic shape that you can imagine.  You can control the sharpness of corners so that everything doesn't end up looking like PlaySkool toys.

Start with in the Object Editor with the front view filling the screen.  Add a Cube  and double click on it to show it's properties dialog.  Set the number of divisions in the X, Y, and Z axii to 3, 4, and 1.  Set the size in the axii to 30, 40, and 10 units.  Close the dialog and convert the Cube to a Mesh with the Build->ConverToMesh menu command.  The image at the right is a wireframe Ortho view of the result.

This cube will form the basis for making the palm of your hand.  You will extrude the fingers and thumb from the edges.

Now you switch to point-edit mode  where most of the work will be done.  This also switches the screen into wireframe and shows individual points as well for easier editing.  Make sure that you're in the Front view.  Switch to point mode  and drag-select .  Drag select the next-to-top points on the left edge of the model.  Since you are using drag-select both the front and rear points will be selected.  Then change to move  mode and move the points slightly up and to the left as shown.  Continue down the left edge moving points out to form a curve as shown.  This will be the outside edge of the hand, away from the thumb.

Be careful not to move any points in the top row!  These will be extruded later on to form the fingers.  If you move them even slightly then your fingers won't form properly.

Now you need to indent the front of the palm, and bring out the back side so they aren't so flat.  Switch to the All view in the Point Editor.  You will move the eight points hilighted at the left one-by-one.  The back of the hand is facing you in the Front view, so yo need to move these points out towards you.  First select one of the points in the Perspective view using the Arrow Select  tool.  Then switch to Move  and in the Side move the point to the left a small amount.  You can use the arrow keys to do this for precise control.  Continue moving points in this manner until they are all done.  Your palm is now finished.

Next you will extrude the thumb out of the side of the palm.  Still in Point Editor, switch to the All view.  Switch to face mode  and select the next-to-lowest face on the right side of the palm.  It's probably easiest to do this in the Perspective view area.  Now extrude  that face out to the right about 10 units.  Next switch to point mode  and in two steps, drag select each pair of points to turn the face up a bit like the image at the right.

Now do two more extrudes and turn the end up a bit more each time to make the basic shape shown in the next image.  That's all it takes to make a thumb!  You might want to experiment with making the middle joints larger or other variations to see what effect they have on the final model.

I made two: one called "skin" with a color of R=241, G=184, B=142, and Specular=0.4 and Roughness=8, and the other "nail" and has a color of R=250, G=225, B=202, Specular=0.3 and Roughness=10.

Select all the faces with the drag-select tool.  Click on the "skin" material in the Material Toolbar and then on Apply.  Select View->Full to see how it looks.  Then select just the 4 fingernails, and apply the "nail" material.  Deselect everything and you should see something like at the left.

Select your model.  Then select the Build->SubdivideFaces menu item.  Leave the tension value at the default 0 in the dialog that appears, and click OK.  Then do the same thing again. Your model should look like that shown below!

Straight fingers are pretty boring.  Using a couple of modifiers can really help here.  First make sure you're in the front view.  Click on the add modifier tool , then click on the lower part of the small finger and drag up about 2/3 of the way.  Select bend modifier from the dialog, and a yellow modifier grid appears.  It may not be visible if it's narrower than the finger.  If so you can either switch to wire frame, or just continue and it should become visible.

Next select the scale non uniform tool  and click and drag the left mouse button to the right until the modifier is slightly wider than the top part of your model.  You also need to rotate the Modifier by 90 degrees around the Y axis with the Edit->Rotate->RotateY90 command.

Select both the model and the modifier (you can use the right mouse in point-select mode to add additional objects to the selected list) and click on Build->Modifiers->BindModifier from the menu.  Then double click on the modifier and set the bend angle to 105 degrees.  If there are long, jagged tears in the model, then you have included either too much or too little of the model within the modifier selection rectangle.  Undo the Bind and adjust the size or position of the Modifier and try again.

When you are satisfied with the results, apply the Build->Modifiers->Effect command to complete the change.  Continue adding Bend Modifiers until you have positioned the hand as you wish.  You may want to set the Smoothing Angle to something like 75 degrees to keep it smooth looking everywhere.