You don't need to remove the cover. Nothing for you to do there, don't worry about it. All you want to do is to replace ATF, unless your manual specifically says to replace the filter as well. You want the engine to be hot, not cold.
You may want to check the level of ATF now, just so you learn how to do it, and to see what the level is before the change. Measuring ATF on Honda engine is different from other makes - engine needs to be warm (say after 20 min driving), park on leveled surface, turn the engine OFF, then immediately measure. Presumably the level is within range, and if it is, you want to end up at the same place after drain and fill. That's why you measure how much came out, so the same amount goes in. Unless you have some sort of problem, 3 quarts will come out, and 3 will go in.
1. Locate the drain plug
2. Make sure you have the right socket
3. put gloves and safety glasses on
4. put drain pan underneath
5. open the plug and let the ATF drain out
6. when fluid stops dripping (15-20 min, don't wait longer unless you want to), put new washer on the plug and tighten it
7. measure how much came out
8. fill it with new ATF; you have 2 options: AT filler hole, or through dipstick hole; AT filler hole maybe hard to get to, so it's generally easier to use very small dipstick hole, in which case you need turkey blaster because that will fit in there, and your funnel fits into turkey blaster tube; put in the same amount as came out
Note: experienced mechanics and Honda technicians will not measure the amount of drained fluid. As long as it looks about right, they will put in 3q of ATF and be done with it. Since you are new to it and do not want to over or under fill and potentially damage your AT, it's a good idea to measure just to be sure. It should be 3q exactly on most 4 cylinder Hondas. Look in your manual what the exact capacity is, it will be there. Measuring will also force you to take a look at the color and smell of ATF. If it looks really brown, like a used engine oil, and not pinkish-red, you know it should be done again.
Start it up, let it idle for a few minutes while you change gears, turn it off, look at dipstick. If it's in the specified range, turn it up, and take it for a ride. Shift between gears many times, drive, reverse, 1-2, 3-4 etc. Just play with it. Come back home, turn engine off, measure. If within the range, you are done. Congratulations.
If you want to do it multiple times, here are couple of additional tips:
1. After the first time, you know exactly what you are doing, and it will take you15-20 minutes max (most of it waiting for fluid to drain), so you can plan for less time.
2. You can do it in the same afternoon, or on different days, it will not make a difference.
3. You will know when the last one is done - when the ATF coming out is pinkish-red color. It could be the very first time, or the 3rd or 4th time.
4. Keep reusing the old washer if you do it all on the same day, with just short test drives in between. Put in the new washer when completing final change.
While you wait for fluid to drain, look around in your engine compartment. Get familiar with it. Check other fluid levels. Are there any leaks? Does anything rattle? Anything loose? Are all clamps on tight? Air filter dirty? Belt showing signs of wear? Any plugs hanging disconnected? To me, this is where DYI really helps - you will be able to just take a quick look and identify current or potential problems, before any big problems develop. You would be surprised how many times the car that just came from a mechanic (or a dealer) is actually in a worse shape than it was going in.
Don't be afraid. Once you do it, the second time is a breeze and you will feel confident. After that, it will become routine, and you will wonder why you ever bothered getting it done elsewhere - it's like you don't call someone every time you need to unload and reload dishwasher, do you? You will want to move on to differential, which is even easier. You will buy fluids ahead of time only on sale, saving even more money. It will have snowball effect.
Good luck, and please let us know how it went.