Help getting started please

So this is my first post and I'm totally new to bitcoins.
Have been reading alot but still not really confortable with all this...

Basically, I just wanted to change some EUR in BTC to do a payment...

Here's where I'm up to now:
- I opened a BTC-e account to access the trading market
- When I tried to transfer some EUR onto it, I only had two options, one of wich was an OKPAY transfer. No option to wire directly money from my SEPA bank account to my BTC-E account...
- So I opened an OKPAY account which was set up and verified overnight
- I then ordered a wire transfer in EUR from my bank to my OKPAY account using the free "SEPA" method
(waiting for the funds to show up, probably tomorrow)

As soon as these funds show up in OKPAY, I well be transferring them to BTC-e (1% fee apparently).
Then what?
When I will place my first BUY order for bitcoins, and it goes through, I suppose my funds will directly appear in the BTC balance of my account? Does my BTC-e account work as an e-wallet of some sort?
And then, can I do my payment directly to the vendor through BTC-e by using the BTC withdraw button and directly using the vendor's wallet address?
Can I keep the remaining bitcoins "sleeping" on my BTC-e account or do I also have to transfer these to an ewallet on my PC? or should I transfer them to my OKPAY account?

Sorry for dumb questions but still a bit confused as to how all this works...
And I don't feel the need nor desire to host my own wallet as I will only be using bitcoins for occasional single payments, not holding on to them in the long run.