First time installing a sub. Need help

I recently bought a 300 watt 12 inch sub for my 2013 Tundra SR5. Quickly realizing I am in over my head and I have a ton of questions. Along with the sub I bought a 600 watt 2 channel amp. Upon further research its looking like a 2 channel amp was not the way to go and I shouldve gone 4 or 5 channels. Anways heres a few questions I need answered.
Can I connect 2 door speakers and the sub on a 2 channel amp?
Do I need a lineout converter for the head unit?
Also is it possible to just run the sub without wiring any door speakers to the amp?
Any help would be greatly appreciated because I am very lost.

Non jbl system and factory head unit

 

Maybe, depends on the ohms of the speakers, sub, and what the amp is stable to. However, I would not because you will want to have the sub on a low pass crossover which would also make the door speakers low pass (no midrange or highs).

Yes, you will need a line converter to use the speaker signal to change it to RCA input for the amp.

Yes.

 

Ok so if I just wire the sub through the amp then will my door speakers still play? And what wire do I tap into from the head unit to the amp?

 

Depending on the amp, if it's ok with a low power input, you can just tap whatever door speakers wire is closest and run it from there.

Otherwise there's premade harnesses that'll feed from behind the headunit as well, little more work to get to, but cleaner in some respects.

 

Ok so let me get this straight before I try anything. Do I tap the speaker wire from behind the head unit or from somewhere else. I thought that I saw something about speaker wires being located under the front seat which is where my amp is going to go anyway. I also have the remote turn on wire which I’m pretty sure needs to be tapped in as well.

 

I used a Kicker 2ch LOC tapped in behind the dash. Kicker 400.1 amp under the rear driver side seat, and a CVT 8 in a custom single port box behind the rear seat. Amp is under the rear seat because I didn't want it sitting on top of the floor vent under the front seat.
Sorry, no picture of the LOC.

 

Some have already given you these same answers but here's my input:

What amp did you buy, brand name and model number?

Can I connect 2 door speakers and the sub on a 2 channel amp?
You could, but it will sound like shit having a full signal to your sub.
If possible return the amp for a 5-channel if you want front and rear door speakers and a sub amplified.
Or you could go with a 4 channel, 2 channels for the front doors, bridge the rear channels for your sub, and run the rear doors off the HU as they are.

Do I need a lineout converter for the head unit?
Unless your amp accepts speaker-level inputs, yes, don't go cheap on it, buy a decent LOC.

Also is it possible to just run the sub without wiring any door speakers to the amp?
Where would the signal for the sub come from?

Do you have an OEM amp under the passenger seat in your 2013.
If so everything you need will be there except the power line to your amp.
You'll need to run fused line from the battery to where ever your amp is going to be..

The remote wire can be any 12v accessory in the truck.
There should be an ACC lead into the radio.

 

I understand the getting power to the amp and I’m good with that. I have no amp underneath passenger seat. I bought a 600 watt boss audio 2 channel amp from Amazon. Still not sure if I have it right but running a 2 channel loc out the head unit to the amp should work right?