Recommended Free Audio Programs

[Menarker]

Hey everyone, I can use some advice.

I only rarely add new songs to my cellphone but now there are a few songs that I really really want to add (some from Youtube). However, some of the songs are either a bit too long or too short, or they got some annoying audio 'watermark' at the beginning or end of the track which I really don't want to have to listen to each time.

Thus I'm in the 'market' for a decent audio program which will let me alter these tracks in a generally minor fashion. I'm severely hard of hearing (I'm using my special FM device to act as my headphones) so I probably won't be tinkering much with the bass or things like that, but mainly just trimming the fat out of tracks, copying parts of the song to make it "extended" and other generally basic tools.

Factors I'm looking for:
- Safe: Obviously don't suggest dubious programs that may or may not be riddled with viruses, adware, malware and such.
- Relatively simple interface: I'm not an experienced audiophile due to my general lack of interest in audio tech due to my hearing loss, so a program that keeps it streamlined and simple (or can explain things clearly and unambiguously) will be much appreciated.
- Performance: Simply, that it does the job of modifying what I need modified and nothing else beside that. Note that the tracks will be exported to my cellphone, so the tracks should be able to play on that afterwards.
- Free: It's in the title. I'm just expecting a minor touch-up of tracks, not creating a new magnum opus. I don't really want to have to pay for it.

Any such advice would be much appreciated!