General flash question

So I picked up a flash awhile ago and just getting back into shooting , anyways I picked up the manual for the flash and it still just seems foreign. I know they have 5 modes on the flash. ttl, multi ( I think ) m, s1,s2. Now I know s1 and s2 are for slaves but can someone explain to me the other 3 modes and which one should be used for flash noob. After reading it and messing around with the flash, seems like ttl is the most user friendly.

If you want to post links that will help, feel free so I can read.

Ttl is through the lens metering, which means the flash fires a preflash which is used to gauge how much power should be put in to the actual flash. It basically is an auto mode for your flash.
M is manual, which means you have to set the flash power manually, and it will not change.
The multi mode though, I am not sure about.

"Multi" sets up your flash like a strobe light. You dial in the intensity, number of flashes, and flash rate (Normally in Cycles per Second, or Hz) and when triggered, you get the strobe light effect.

Good for simulating multiple exposure. It doesn't have a ton of use, but, it's pretty cool for some special-effects type shots.

List your flash brand and model, as we will be able to determine if that flash supports digital ETTL, or if 'TTL' refers only to the (incompatible with digital cameras) film camera TTL.