If you managed to import the make human model and you can see it in blender, do the following:

In the right panel you can see a little human figure icon, between a chain and a bone, This is the object data. Down in that tab find Visualisation option, mark xray, then you will see the rigging in your figure, select some bone of your model.

You have a boton under the blender interface "Object mode", unfold the list and chose Pose mode.

Select whatever bone. press R key (to rotate) and and move the cursor, You will see the move. Left click to stop
crtl+z to undone that move. Prove press R key + X key to move only over the X axe. And that's the way you can start tu put in whatever posisión your model. But I'm a complicated man... here is a good tutorial: https://www.youtube.com/watch?v=MQBtZgWyrI4