Getting started to work on my 1974 Dart Sport. I got questions

You said the car has sat for a decade? First thing I do is pull the gas tank, IF it had any gas, dump that, pull the pickup and use light etc to see inside tank's condition.
Clean the car inside and out.
Make list of all the mechanicals that probably need to be addressed for a safe ride.\
Go from there.

What you can achieve depends on your desires, money, and skill level. It is usually obtainable for any one that desires it all.