What's the difference between distortion pedals and overdrive pedals?

They are essentially the same effect. Distortion is an extreme kind of overdrive. ‘Dynamics’ are the difference between your loudest playing and your quietest playing. Light overdrive will preserve your dynamics whereas distortion will compress them to the point where all your notes are the same volume and have a long, singing sustain.

How to stack overdrive and distortion?

A good starting point is to put the pedal with the least 'Gain' first and the highest fain pedal next. But as with music it's good to experiment! So feel free to move all your pedals around till you find your sound.

Do I need both overdrive and distortion pedals?

Of course not, but it can't hurt to have extra versatility! Your pedalboard is yours and you should load it with pedals you love the sound of.

Should I get an overdrive or distortion pedal?

Without wwanting to say ‘you should get both’, you should get both! Players often use overdrive and distortion in tandem, using distortion for riffs, choruses and solos and using overdrive in verses and lighter songs. Overdrive and distortion pedals work really well when ‘stacked’ in the same signal chain, creating a wider range of gain and tones.

Where does my overdrive and distortion pedals go in a chain?

Overdrive and distortion tend to go near the beginning of the chain - before modulation pedals and time-based effects, like reverb and delay. If you are using both overdrive AND distortion pedals, players tend to stack these in order of gain. Plugging the guitar into the lighter gain overdrive pedal and then into the higher gain distortion pedal works well.