If you're still starting out, you just generally use one team for offense and defense. 

I'm confused by your questions... which could be on me, or it could be because you misunderstand arena defense. So if you already know everything that follows, sorry. ;) 

You can check the results of your arena defense team in the battle log screen, defense tab. There you see the people who attacked you recently and the outcome of these battles. You get no other notifications of people attacking you in arena, because anyway you don't get to actively play in arena defense, it's just the AI running the team that you have chosen as your defense team. The only way you could notice getting attacked, other than looking in the battle log, is that your arena rating decreases or increases without you attacking anyone. Your question above describes you attacking someone - so that's arena offense and has nothing to do with arena defense. 

The reason that I advised to put the same team in arena defense as in arena offense, is that you need more or less the same things in terms of speed, tactics, synergies between your champions. The only differences are that 1) it will always be the AI running your team, so you may want to avoid some champions with particularly stupid AI, and 2) your opponent can see your team in advance and adjust his attacking team accordingly, just like you do yourself when attacking in arena. So teams which can easily be countered by a prepared opponent, are at a disadvantage in arena defense. 

As LXZY said, you'll probably lose the large majority of your arena defense battles, but that's because you can't see the people who never even attacked you because they were afraid they would lose. So your arena defense may still be quite successful even if you see very few victories. In any case, losing on arena defense isn't a big deal. Yes, it decreases your rating, but as long as it doesn't get decreased too far too fast, that's not a big problem and you should still be able to climb to whichever tier you belong in based on the quality of your team. Actually, sometimes you'll see people who deliberately put an extremely weak defense team, like 1 low level champion, because they feel their rating is too high and they can't win enough battles anymore, so they want to drop back to a lower tier. Which is a win-win because at the same time it provides wins/medals by default for other players who encounter that defense team in their offense list. 

@L9753......Thanks.  I was confused about arena.  I farmed Valdemar for 2 days to get Templar to drop.  I thought he would be good in arena defense.  I got Goremask from a shard and thought he could be arena defense.  For now, both are just sitting while I push Kael to 60. 

I wondered why my arena score was going down.  I was about to blame my cat for playing the game poorly while I wasnt watching.   lol

If you run multi-battles, you can set it up to automatically sell artifacts below a certain level (but don't do that during Dungeon Delver events in which you get points for each artifact you gain, like the one that's running now... then you should make sure to get each artifact and its corresponding points before you sell it). For battles that you run one by one manually, just sell the artifact for silver directly from the victory menu.  

Also, for artifacts that aren't good enough for your main champions but not completely terrible, instead of selling you could put them on secondary champions which you will use at some point in Faction Wars. Faction Wars are a long way down your priority list now, but still they do offer some useful rewards and you won't get far using champions with no gear at all.