[CrowMech]

I recently bought a used Suzuki marauder 125cc, it was running fine, as fine as a cheap used bike will run, i rode it for like 200 miles on one filling of fuel but today i went to fill it up at the petrol station and filled it up, (i don't know if i fiilled it up too much, this is my second time doing it ever) after paying and getting back on i turn the ignition key, the lights lights turn on and i try to start the bike but literally nothing happens, i keep trying and nothing happens, i rolled it home but i don't really know how to fix it. This is my first ever bike, first ever anything like this in general so i don't really have any experience. Please help

 

[MotersickleBum]

check the battery connections and make sure that that battery is fully charged. also check the kickstand switch.

 

[Miss Mercedes]

Welcome to the site!!!
I had a few bikes do similar to me. It sounds your starter doesn't even turn. Here's my path of troubleshooting:
1. Check battery connections. If they aren't super tight, the engine can vibrate the screws free.

2. Test the starter and start solenoid. If step 1 revealed tight connections, you maybe have a bad start solenoid. Short the two posts on the solenoid together using a screwdriver. If the starter spins you probably have a bad solenoid or bad start switch. If it doesn't, you either have bad wiring, a dead battery, or a dead starter.

 

[grumpyunk]

Use a VOM to measure the voltage across the battery terminals. If less than 12v you need to charge the battery. Even at 12V your battery is not charged fully, full being closer to 12.75V.
Check that your interlock switches have not disabled the starter relay. Some have kickstand switches that don't let the electric starter work until the stand has been folded up out of the way. Some have brake switch interlocks, requiring a brake lever to be pulled while cranking. Some need the transmission in neutral. Some have none of the above...
You can check yours for 12V at the small terminal(s) on the starter relay. The bigs go to the battery and starter, the small, one to the starter button to supply power/ground to the relay winding, the other(if equipped) to ground to provide a path for the windings. Most have two small wires. One ground, one HOT when the button is pushed. Use a 12V test light to check, key ON, starter button pushed, the light should light. All the above if you have a good battery, with good cables and tight terminals.
tom