[Q] HELP! Wiped system files now can't boot up the phone (says no OS installed) topic

Sorry but I'm a total rookie here. I first started screwing around with my stock Nexus 6 by rooting. Then somehow I ended up with TWRP installed (or whatever) on my phone. Today I received notification that 5.0.1 OTA was available and when I click install it just went into TWRP and wouldn't let me install the update. For some reason I messed with TWRP and erased everything. Now I'm stuck with a brick.

Oh an to boot I can't get Android SDK running on my computer because of JVM or something.

Can anyone help? I just want to go back to out of the box stock and start over if that's possible. No TWRP or rooting necessary for me after this episode.

Thanks so much in advance for the assistance (please use small words and short sentences). Yes, I've tried searching like crazy and can't find anything that just step by step instructs me how to get back to stock.