The default inputs for waling around are
W to walk forward
A to strafe left
S to move backwards
D to strafe right
More advanced players may change these inputs in the controls menu, if you did you can view these inputs any time in the controls menu and even change them to what you'd like by clicking on the input you want to change and pressing the key you want to change it to.

To look around you move your mouse in the direction you would like to look. If you have controls set to inverted you will move your mouse in the opposite direction you want to look.

You can combine these techniques together to create advanced techniques. To do this you will press the key to coordinates to the direction you want to move (section 1 if you forgot) and move your mouse cursor in the direction you want to look at the same time. This technique is called patrolling.

For this final section I will teach you a very advanced technique called sprinting. To sprint you will press the key that coordinates you to move forward and then hold down the ALT key to move faster. This is another technique that can have its input changed in the control menu the same way you do with the walking inputs.

***DO NOT ATTEMPT***
Whatever you do do not attempt to combine sprinting and patrolling without at least 3 years of training.