[mrlmd1]

It sounds like your battery is discharged, Charge it up again, bring it back to the store you bought it from and have them do a load test on it. and that will be free. That is the only way to see if the battery is any good.
You may have gotten a bad battery altho that is unlikely, but maybe it wasn't fully charged when you started using it.

That thing from Walmart is not a multitester, it is a continuity tester. You need something that will measure voltage, and that is a multitester - if you don't know what it looks like or can't find it, ask a salesman.
You just connect the pos wire to the pos battery terminal, neg to neg , make sure the scale is set right, and read the voltage. A fully charged battery should read 12.6-12.8V. The instructions for using the thing are in the package, and you really can get a decent one for less than $10 at an auto parts store or Walmart, Lowes, etc.
You do not have to know the exact rpm - anything above a fast idle, less than midrange rpm, should put out sufficient charging voltage, and with the meter connected to the battery, that should read 13.2-14V depending on the state of the battery if everything is working.
Get that voltage measuring multitester and have the battery checked before you bring it into a shop. And also make sure your battery connections are both clean and tight.
You can diagnose this, it's not really nuclear physics or quantum mechanics (or rocket science).
FYI, the charging system on this bike puts out very little juice at idle. You cannot charge the battery with the bike sitting in the driveway idling for 15-20 min.. You will use up more juice starting it than you will replace into the battery doing that, besides the bike overheating from lack of cooling air flow around the engine - not a good idea prolong idling.