Sounds a bit basic but do ensure first of all that the gear selector is in P or N, and if it is in one of these move it to the other and try again.
In the time it all took maybe your battery has run down a bit. Check it or give it a trickle charge.
I am a very strong non-believer in coincidence. so I don;t believe that a car that started and ran before you did work on it, and is now not starting, has suddenly developed another fault.
So I think the fault is linked to whatever you have done.
So go through all you did and make sure that the battery is up to full charge, that the connections to the batt have not been disturbed, or if you undid them then that they have been remade properly. Make sure anything else that you undid hasbeen put back together.
Shut the car bonnet and door. Lock it with the fob, then unlock it, get in and try to start it. As
@sierrafery said.
Then it may possibly actually be the starter. To be sure of every thing else first, ensure all connections from the battery earth to the engine are good and solid. If the starter clicks but doesn't turn over, if the power to the starter is up to snuff, i.e. about 12.65 volts, then you are looking at a bad connection inside the solenoid. To begin with this can be overcome by clicking the key over and back until eventually it starts. Mine has been doing this until I got the kit and took the starter off to renew the contacts in the solenoid. This is where, once you turn the key to its final postion, the solenoid not only clicks in to get the drive pinion to position itself where it can drive the starter ring gear but also, it makes an electrical connection which allows current to pass through the starter motor and thus turns the pinion, turns the engine over and the engine starts.
This is a common fault, I fixed mine the other day and put a thread up telling others how to do it as it is not straight forward. The main problem being getting one of the mounting nuts off.
Let us know how you get on.
