I started playing... IDK... it's been pretty much my entire life, my dad used to set me on his lap when I couldn't even look up and play Tiberian Sun. Later, when I had some muscle movement and had a decent idea of how to open something(most of the time, my dad still opened it. I was only like... 9 months), I used to play it. Well as much as a 9 month old child could. I later found my brother's copy of the Decade Edition when I was 4. Loved the hell out of it, and loved messing with RA1's map editor.
Eventually, I got the ultimate collection(which BTWs is a ripoff, don't buy it-you should just pirate from EA like I did for Red alert 3 and C&C 4 with my cousin's account-I own it now though. Does that count as a rule break?).
So Kaskins, I'm going to lay this simple:after beating Red Alert as the soviets, you immediately move into the Tiberian Dawn(and CANONICAL) timeline. If you beat the Allied campaign though, well, you move into RA2. RA3 just throws out RA2 and RA1, and very well could've just been a reboot at this point.
Tiberian Sun is a game that, honestly, could've been better if it wasn't for EA. Look up a ton of old Pre-E3/E3 pictures of TS and you'll find these massive cities with great huge battles. Now if you look at it now, there's small cities and not quiet the selection of units. Also got rid of my favorite unit-and I cannot fix it thanks to a bug which involves the very first patch EA released for TS-the ORCA Transport. Still a good game though, and if you're into more of a COH battle system.
(thanks to bad grammar I can't exactly tell what you're saying by the ways. This is just my assumption that you were asking about it and all.)