I agree that CFP is not the most "newb-friendly" firewall in the world, due to the level of its complexity; at this point it's a bit of a trade-off (security vs easy). A number of users have requested more "user-friendly" features, which I think is probably a good thing. However, I am confident that regardless of your computer skill level, this firewall is not beyond your reach.
If you're on a hard-wired router/modem (which you've said you are), then you don't have much to worry about with those log entries, in my opinion. There's always a possibility that someone has physically connected to your home's wiring, etc but that's probably not very likely.
That said, you can do one of a couple things:
1. Ignore the logs as long as everything seems to be working (ie, you can browse, check your email, etc).
2. Automatically create a Zone that will encompass them (Security/Tasks/Add a Zone) and then set that as "trusted" (Security/Tasks/Define a New Trusted Network).
3. Manually create two Zones - one to allow the current IP Configuration (as per my earlier post) and set that as a Trusted Network (as per item 1); one to define everything from that point through the end of the IP range, and use that Zone to define a Block and don't Log rule in your Network Monitor.
Item 1 is obviously the easiest; however, you get a lot of "clutter" in your logs. This is the "ignore" approach.
Item 2 is VERY EASY to do (it's almost fully automated); it will allow the traffic automatically and won't clutter your logs. Given you're not wireless, this is the "set and forget" option.
Item 3 would the one for the PC junkies...
If you wanted to do so, it's easy enough, and any of the Mods here (as well as any number of other users) can walk you through that.
Hope that helps,